This website is grounded in my “Conceptualizing World History,” World History Connected, Summer, 2024. https://journals.gmu.edu/whc/article/view/4175/2348 That paper suggested that we can provide coherence (and enhanced understanding) to world history by recognizing three broad types of historical change as well as three broad types of recurring historical patterns. In this website we summarize how these three types of change and three types of recurring pattern occur in the different periods of world history. Szostak (2024) also recognized the importance of historical contingency; we will discuss key types of contingency for each time period. I draw heavily on my Making Sense of World History (Routledge 2021) in fleshing out this Timeline. Yet I invite you to email me at rszostak@ualberta.ca if you think I have missed something important.
The three types of change are historical transformations (that is, changes that make other changes possible), trends, and evolutionary processes. We describe the most important of each for each time period. We also summarize how these together drive changes (or not) in each of the ten themes described in Szostak (2021): culture, population and health, social structure (divisions by gender, class, ethnicity etc.), politics, technology and science, economy, art, non- human environment, and [for the period of human evolution] basic human capabilities and human diversity. It is a useful exercise to detail the most important changes by theme in each time period.
The first type of recurring pattern involves causal relationships between themes. Through most of history, increases in human productivity resulted in increased population and thus limited impact on average incomes, for example. We can highlight when a particular regularity begins or ceases to be important.
The second type of regularity involves the limited sets of choices that human agents face in addressing common challenges. Rulers throughout history have a handful of ways of encouraging bureaucrats to do what they want, for example. We can highlight when new types of agent emerge, and if the range of challenges or strategies increases.
The third type of regularity involves forces driving similarities or differences across regions. This is a central concern of world history. Though there are regularities – trade is in general a force that encourages similarity – we can summarize for each time period in what ways regions are diverging or converging and why.
As noted above, we can also highlight for each period important types of historical contingency.
We try to brief in what follows. We thus try to focus on the most important types of change and regularity. And we cannot go into great detail on why any of these occurred.
A brief note on periodization: I see periods as matters of convenience, breaking history into more manageable chunks of time. We should not imagine that there are dramatic changes in all of our themes as we move from one period to the next. Indeed we should be as interested in continuities as in changes. I do identify periods in terms of key transformations, but that does not mean that these transformations drive everything that happens during that period. I also note that the same transformation may occur at quite different times in different regions. [I rush to note that I also think it is important to try to get a sense of what life was actually like in different times and places. We will not do that here but I do think it is important.]
1. Big History Prelude (from the Big Bang to hominids)
There are compelling natural science explanations of how the universe, galaxies, stars, planets, our planet, life, species, continents, and other aspects of our natural environment came to be. Some of this scholarship is very new, and there are still questions such as what predated the big bang (how can something come from nothing?), where and how exactly life first emerged, how complex organs like eyes evolve, and so on. Yet we should appreciate that for the first time in human history we have a compelling scientific understanding of how the natural world came to be. We can seek to add a similar understanding of the emergence of the human world. We should be careful not to assume that similar processes were at work. Yet it seems that in both histories there is a place both for stability/gradual change and major transformations (star formation, emergence of life)
Transformations: Elements, stars, planets, continents, life, species
Trends: Big historians often stress a trend toward increased complexity (though we should be careful of assuming this need also guide human history)
By theme: Humans do not yet exist, and so we only address the non-human environment
Regions: Plate tectonics explains the formation of continents, and of most mountain ranges (volcanism explains the rest). Glaciers created flat plains on many continents.
Contingency: It appears that there was a great deal of contingency along the way. There needed to be some uneven-ness in the big bang itself for matter to form stars and planets. It appears that life is only possible within fairly narrow environmental bounds. The formation of the Isthmus of Panama had a huge impact on weather patterns globally. Biological evolution is driven by random mutations, though this is guided by the natural environment (which selects some mutations while rejecting others).
2. Human Evolution (the hundreds of thousands of years before agriculture)
Theories of biological evolution help us to understand why humans developed particular abilities and characteristics within a particular natural environment.
Transformations: Humans, Language, which is costly but needed for social cooperation and/or toolmaking. Bipedalism, which reflected the savanna environment. Fire and tool-making. Migration
Trends: Population size is limited by the practice of hunting and gathering. It expands a bit as humans develop tools and fire-making, and more as humans migrate into new lands. Economically, human diets may improve a bit with knives and fire. Humans develop better clothing and shelters.
Evolutionary Processes: Note that for all later time periods we speak only of different types of social evolution. Only here and above do we engage with biological evolution. Questions remain about whether human language capability emerged mostly for socializing or toolmaking. It both encouraged and reflected a gradual increase in the size of the hominid/human brain. We can only speculate on what changes occurred within the brain, but our abilities to speak, design tools, and manage social relations likely improved over time.
Once humans develop tool-making capability there is an evolutionary process of developing better technology.
We know that culture and genetics co-evolve during this period.
There is clear evidence of evolutionary change in artistic practice (at least for cave drawings)
Human abilities etc.: Walk, speak, tools, fire, but also self-deception, altruism
Human diversity: With language especially, human groups will benefit from personality diversity. Different humans can then perform different functions.
Culture: Though we do not know the details, we know that cultures co-evolve with human genetics. This is the best explanation of selection for altruism. Religion appears early though we do not know the details
Population: As noted above, population grows through migration, technology
Social structure: It seems that hunter-gatherer bands were egalitarian. Women and men often played different economic roles but both were valued. There is debate regarding the level of hostility between different bands: there is some evidence of conflicts but also of trade, interbreeding, and even shared religious beliefs.
Politics: Egalitarian though some organization of hunts; question about incidence of war (see above)
Technology: Toolmaking; range of tools expands through time; fire-making
Economy: Better food with fire and knives, clothes, likely shelter; some trade
Art: We see works of art from about the time of toolmaking; statuettes, later cave drawings (which get less realistic over time as artists draw on art rather than life for inspiration)
Environment: The emergence of African savannah may have been crucial to the development of bipedal humans. Human migration was then shaped by both climate and ease of movement.
Recurring Patterns: We expect that the “Malthusian” dynamic increases in productivity (due at this time largely to technological innovation) result over time in increased population rather than dramatic increases in income – operated throughout this period. It would continue to be important until the modern period.
How Humans Face Recurring Challenges: We suspect that there was little occupational specialization at this time. We have doubted above that there were powerful rulers. It is unknown how trade occurred: were there merchants? Art may well have been a communal activity, but the tendency of cave art to become less realistic over time may reflect a challenge faced everywhere by artists: to innovate but not so radically as to offend their audience.
Regions: With fire and clothing humans expand to most places that we inhabit today. All humans pursue hunting and gathering (with some fishing in some places). We know little about differences in culture or art; there was fairly long distance trade in batons which suggests some shared religious belief. Nevertheless, as humans migrate long distances, some human groups become effectively separate, and thus develop independently. Humans generally carried tools when they migrated, but then developed different tools in different regions.
Contingency: Without the emergence of the African savanna, there may be no humans; genetic evolution always depends on mutations though the selection environment may have strongly favored bipedalism etc.
3. The Development of Agriculture, Nomadism, and Fishing
Transformations: The development of agriculture is one of the greatest transformations in human history. It in turn depended on a cluster of smaller transformations including myriad technologies for not just farming but also storing and cooking the resulting food products, as well as social arrangements governing things like land ownership and sedentary living. Nomadism (which came a little later) and fishing (which predates both but was only possible on a large scale in a few places at the time) are also both important and likewise involve many smaller technological and other transformations.
Once sedentary agricultural populations are in place, we see a host of further technological innovations over time: smelting various metals, pottery, brickmaking, glassmaking, advances in textiles (cotton, linen, wool, silk). These are each transformative (note that some hunter-gatherers made some pottery and textiles).
We should also mention both merchant networks and money.
A new type of religious belief emerges with agriculture (see below).
Trends: Population grows with agriculture (and to a lesser extent with nomadism; fishing supports large populations in a few places). Sedentary living allows humans to build nicer shelters and accumulate more goods (clothes, cooking and eating utensils, and more).
Evolutionary processes: Though we focus on a few big technological innovations in our discussion of transformations above, we should appreciate that there is in fact an evolutionary process of slowly improving a range of technologies over time. There is also an evolutionary process in art, as artists seek to innovate but build on what went before (with some borrowing from other societies). A process of institutional evolution begins as complex societies develop – see our discussion of cities and states below. Though we know little about it, there must also have been a process of cultural innovation as humans grappled with the challenges of large sedentary communities, trade, migration, hierarchy, occupational specialization, changing gender roles, and more.
Culture: As is often the case in history, we know the most about changes in religion. Hunter-gatherers seem to have been animistic for the most part but farmers had greater concerns about rainfall and flooding and developed (often annual) ceremonies invoking generally polytheistic gods with different responsibilities over natural processes. While we can identify similarities in the purposes of these ceremonies and gods there was clearly scope for considerable societal diversity in the gods imagined and ceremonies pursued – and thus the nature of the priesthood involved.
Population: As Malthusian theory would predict, the main effect of agriculture itself, and then of later advances such as irrigation or (bronze then iron) plows is to drive a big expansion in population. Yet sedentary living and increased trade lead to the spread of a variety of diseases and frequent epidemics. The trend of population increase is thus irregular.
Social structure: Agriculture (and to a lesser extent nomadism) leads to gender stratification. This is accentuated by the development of heavy metal plows, which are generally pushed by men. [Increased frequency of war may also be crucial here.] There is considerable occupational stratification with rulers, merchants, and artisans especially.
Politics: Agriculture, fishing, and nomadism are all associated with hierarchical political structures. There is a dramatic increase in the incidence of war (it seems; again we are not sure how warlike hunter-gatherers were before the development of agriculture) and of formal armies and military weaponry. It may be that agricultural settlements were fairly peaceful at first: walls and weapons come centuries later.
Technology: Agriculture itself, plows, irrigation, fermentation, horse domestication, metals, pottery, brick, glass, textiles, wagons, boats
Economy: As noted above, there is likely a sluggish increase in incomes as humans build better houses, pots, and clothes. There is, though, decreased diversity in food consumption (though trade may alleviate this a little). Economic inequality increases as a small elite (and small middle class of artisans and merchants) emerges. Trade expands a lot, especially as specialized merchants and artisans emerge, merchant networks are developed, and better wagons and boats (and sometimes roads and harbors) are built. The development of money is a key transformation.
Art: There is an increase in both the quantity and quality of art. Sedentary life encourages the construction of government buildings, temples (note that hunter-gatherers sometimes built religious structures) and statues. These buildings were then richly decorated. There were then technological developments in building, paints, casting of statues, and more. A specialized class of artists emerges in most societies that pursues both technical and aesthetic innovation. (note that art from this time can still be appreciated today; there is considerable diversity across societies but also borrowing)
Environment: There is a debate about the degree to which some agricultural populations later declined due to harming their own environment. Though some agricultural practices can decrease soil fertility over time, and irrigation may increase salinity, it now appears that most societies adopted strategies that alleviated these risks. It could be that deforestation caused some global warming and decreased biodiversity.
Recurring Patterns: The “Malthusian” dynamic continues.
How Humans Face Recurring Challenges: Farmers have far more stuff than hunter-gatherers, in large part because they are sedentary. But harvests also have to be protected. Though the earliest agricultural settlements may have been peaceful, farmers eventually need some protection. Building walls around cities or becoming part of a state with an army are possible strategies.
Nomads also need to protect their herds and possessions. Indeed, these are generally easier to steal. But walls and territorially-defined states are not feasible strategies (most of the time). But clans and tribes can combine under a leader to protect everyone’s stuff.
For both farmers and nomads, armies and tribes might pursue offence as well as defense.
Regions: Agriculture, nomadism, and fishing encourage different political, economic, cultural, and social relations. Trade and conflict between them also shapes societies. Agriculture is developed independently in several places but then spreads with adjustments for soil and climate (tastes in food largely adapt over time as crops are grown where feasible). Mining depends on the discovery of minerals: We get trade in minerals over long distances (and some cases of colonization). We see regional differences in art that reflect culture and politics. Yet artists in their efforts to innovate often adapt foreign ideas to local markets.
Contingency: Agriculture can only develop with suitable wild crops and an appreciation that these can be planted. Similarly, nomadism and fishing depend on the availability of local resources.
4. Early Cities and States
Cities and states are one possibility that emerges with the development of agriculture. It should be stressed that this is not an inevitability: the people of the New Guinea highlands develop agriculture but not cities or states. But in most places that develop agriculture we do eventually see urbanization and formal states with bureaucracies. Note that nomadism results in a quite different form of hierarchical political development: clans and tribes. These sometimes result in some urbanization and occasionally but importantly in large states. The interaction between agricultural states and nomadic tribes (in both Central Asia and Arabia) is an important part of Eurasian history. [Nomadism does not exist on a large scale in the Americas due to a lack of appropriate animals]. The fishery occasionally supports some urbanization and localized state formation, but the largest cities and states rely on agriculture.
Transformations: Cities, states, writing, formal education, laws and other political institutions. The increase in the incidence of war associated with state formation (and often conflict with nomadic tribes) may deserve mention as a transformation. We have mentioned new religions above; these are strengthened and institutionalized by states.
Trends: Population continues to grow irregularly for reasons discussed previously. Political consolidation often though not always facilitates an expansion in trade. Political consolidation and trade likely generate some cultural consolidation.
Though the vast majority of the population are still farmers, the growth of cities and states necessarily involves occupational specialization.
Evolutionary Processes: The most import of these here may be institutional evolution. New and expanding states inevitably experimented with institutions. They needed to control growing bureaucracies. And we can trace an evolutionary process in which law codes are promulgated to support trade and maintain social cohesion. Though institutional evolution can follow different paths in different states there are many cases of institutional borrowing.
Processes of technological, cultural, and artistic evolution continue. States try to encourage cultural attitudes and art that support the state. The mandate of heaven in China, and the pantheon of Mesopotamian gods are important examples of cultural attitudes that justify powerful states. Temples and the art within are important examples of art that also supported states. States become an important part of the selection environment for technology, supporting some types of technology (notably military technology) but being suspicious of other technologies that might cause social instability (if for example they threaten the livelihood of certain artisans).
We might make special mention of monuments. States and associated temples build monumental buildings. A specialized class(es) of builders emerges. These develop systems of apprenticeship (often familial). A process of both aesthetic and technological evolution occurs. This means that monuments often become more impressive – both technically and aesthetically – over time. This process can be disrupted if war or epidemic or climate shock results in information not being passed from one generation to another. Sometimes the taste of rulers changes and evolution is guided in new directions (as when Egyptians stop building pyramids).
Culture: States encourage some sense of community but often respect some cultural diversity. States become closely connected to polytheistic religions which justified kings and social stratification. While gods may be identified with a particular city or state they often have roles beyond these boundaries. New gods are often absorbed after military conquests. Though religions at first stress hierarchy and obedience, there are some important signs of a later emphasis on ethics as in the cult of Osiris in Egypt: ethics are important as humans increasingly interact with strangers within large cities. (China follows a somewhat different path with a less organized religion focused on deism more than polytheism – but with important polytheistic elements – but an emphasis on ancestor worship, and the idea that distant gods punished bad behavior, served similar goals). Sacrifices and temples are ubiquitous.
In most societies we get a clear idea of “foreigner” as merchants move. Foreigners are often disparaged but sometimes married and allied with. This indicates that there were clear cultural differences that societies came to celebrate. War fosters strong cultural identification and vilification of opponents.
Population: Urbanization and trade foster diseases and epidemics (which can have huge economic and political consequences in the short term). Some industrial processes, and the challenges of clearing human wastes from cities, generate local pollution. Population continues to grow (doubled in the Eastern Hemisphere with bronze and again with iron) despite wars and epidemics. There are population declines due to climate shocks in at least c. 2200 and 1200 bce.
There are mass migrations, especially during climate shocks. The most remarkable of these occurs by boat in Western Polynesia. The expansion of the Indo-European language family in Eurasia is also notable; we are still investigating how much of this reflected conquest, though mastery of horse and chariot may have been important.
Social structure: There is even more occupational specialization (some based on education) as bureaucracies are developed and trade expands. There is ethnic diversity in trading cities because of the importance of ethnic-based trading networks. There is further gender stratification though this differed a lot by state; it is almost certainly enhanced by war. Rulers are almost always male (though we often see female rulers in Kush and Moroe; and twice in Egypt). Early polytheistic gods had families but male gods likely became more important over time reflecting and reinforcing life on earth. Oddly, marriage was not a religious ceremony for most polytheistic religions (States generally encouraged marriage).
Slavery is observed in most states in all parts of the world. It tended to be taken for granted by the vast majority of people everywhere that it occurred. Why? The economic case for slavery is not very strong: At a time when free labor generally worked long hours for subsistence wages, there was not always a big advantage to employing slaves – except in harsh or dangerous employments such as rowing a war galley or in unwanted employments such as prostitution. The sources of slaves may provide some clue: they were often prizes of war that had the advantage that they could walk themselves to market. They were sometimes orphans or criminals or the highly indebted at a time when there were few prisons or orphanages.
Politics: There is obviously increased hierarchy in most human societies. A fear of mob violence may have restrained the abuse of power somewhat as cities grew in size. We see democratic forms of governance in some smallish city states (especially port cities dominated by merchants), but larger states are everywhere governed by kings: It appears that communal governance of large states was not feasible given the communications technology of the time (though kings might let local decisions be made communally). Kings may also be ubiquitous simply because it was possible to maintain power through an army funded by an agricultural surplus (even if early states were only able to tax away 2% or so of total income).
The size of states depends on agricultural productivity and communications technology. Military prowess is often celebrated by rulers of the time, but these often conquered more land than successors could govern. Trade could also be an important source of tax revenue. Merchant networks negotiated with rulers: Rulers were always tempted to steal from merchants but hesitated to scare a network away. The development of currency simplified bureaucratic challenges and allowed states to grow in size.
Human sacrifices were practiced in many early states. This is, among other things, a sign of the power that elites might exercise.
Both merchants and bureaucracies (including temples) play a role in the development of writing. Once writing systems exist, states everywhere promulgate laws. Codification encouraged local judges to pursue the ruler’s wishes. In some states law codes came over time to place some limits on the power of kings, while in others the king retained the ability to simply change laws. States had many motivations: to encourage but then tax trade, to ensure that inheritance proceeded smoothly (so that farms and merchant or artisan businesses continued operating), and to solve disputes peacefully (states generally wished to be the only legitimate purveyors of violence).
The incidence of wars clearly increases with both cities and states. Cities have lots of stuff worth stealing and thus over time build protective walls. Rulers often claimed that they could achieve peace by conquering all foes, but were rarely successful (unless they operated in a constrained geographic environment such as the Nile valley that limited the number of competitors). There were attempts to sign treaties among competing states, but these proved difficult to maintain for long. Wars could potentially provide a tempting financial reward to rulers who could only extract so much from their own peasants.
While rulers were the main potential beneficiaries of war, they employed both ethnic identity and religious fervor to encourage others. Soldiers might also benefit financially from plunder. Defeated populations – and especially women – were often treated harshly, which provided further motivations to be on the winning side.
Technology: Writing!! Both states and merchants needed a form of nuanced record-keeping, especially given human deceit. As noted above, advances in bronze and then iron smelting had dramatic effects on agricultural productivity. They also had huge military implications: States with early or privileged access to bronze or later iron had a huge military advantage. Iron especially encourage an increase in the size of armies. The pottery wheel is another big development in this period, but there are a host of innovations across many fields.
Note that war creates a very intense selection environment for military technology. States that experience peace for a long time may fall behind and suffer later.
Economy: There was increased trade (but merchant networks needed to negotiate with states). A sluggish expansion in average incomes likely continued due to technology and trade (but as noted elsewhere the biggest impact of these in the long run was to increase population). There was increased inequality as a small elite of kings and priests dominated the new states, building elaborate. Though a “middle class” of artisans and merchants also grew, it remained very small by modern standards. In most agricultural states farmers comprised 90% or more of the population. These early states (and perhaps later empires) were likely the most unequal societies in human history.
Institutionally we see the first banks and a variety of merchant contracts. These support a further expansion in trade.
Art: In all regions of the world, states and associated temples build monuments. These have quite different styles but all are designed to encourage awe among the population. A couple of important technological developments are domes and cranes.
Other types of art benefitted from improvements in metallurgy, molds for making bronze sculptures, and the introduction of terracotta.
Note that Imhotep, builder of Egyptian pyramids, was originally from Syria.
Environment: The biggest change here is that states built road networks to support both bureaucracy and trade. Some states also developed large systems of irrigation (though these often expanded on smaller systems that had been developed by earlier more communal systems of government). Pollution near cities continued to be problematic. Some areas suffered from deforestation.
As noted above, climate shocks induced mass migrations. The climate shock of c. 2200 bce caused drought in the Middle East and flooding in China. Both areas experienced economic and political disruption as a result.
It is possible that the decline and disappearance of The Indus Civilization was at least in part due to a climate shock.
Geography shapes states. Egyptian states were often able to control the entire Nile valley. This limited the frequency of war and also the ability of Egyptian peasants to run away
Recurring Patterns: The “Malthusian” dynamic continues.
Independent city states often pursue communal forms of government. Large agrarian states become kingdoms.
The fact that individual states rise and then fall is dramatic but nevertheless a historical regularity. The growing power of local elites and landowners within states may also be a regularity, and an important source of decline.
There were lots of mass migrations. Climatic changes likely drove some of these.
How Humans Face Recurring Challenges: Much of the drama of early states involves rulers figuring out how to control their bureaucrats. Generals and provincial governors proved particularly challenging. Rulers’ attempts to justify their rule were partly intended to motivate loyalty among bureaucrats of all types. Spying/auditing, punishing transgressions (often harshly), and employing foreigners or slaves were common strategies.
Merchants form networks to reduce the risk of being mistreated by other merchants. Merchant networks can also negotiate with states: Rulers will always be tempted to rob individual merchants but will hesitate to offend an entire network.
Builders need to develop relationships with members of the elite. They also need to develop a set of skills and train a workforce. These skills must be passed between generations or important knowledge is lost.
Artisans also need to develop skills and pass these on. Like artists they may seek to innovate in order to enhance their reputation.
Soldiers want to stay alive while perhaps gaining some war prizes. They may be motivated by love of state or religion, or by more selfish financial calculations. Soldiers motivated selfishly are more likely to abandon their positions if they seem to be losing. Soldiers may also be motivated by the opportunity to mistreat enemy civilians or soldiers.
Regions: As with agriculture itself, cities and states emerge independently in several parts of the world. These ideas then spread. Merchants occasionally develop new cities on agricultural frontiers. Some states are formed precisely to provide defense against existing states (e,g, Nubia). Even areas dominated by nomads developed some cities and occasionally state bureaucracies.
Though there were similar reasons for the emergence of cities and states, cities and especially states faced incentives to stress their differences – especially cultural/religious differences. States often borrowed institutional ideas from other states, but might also at times purposely seek to differentiate themselves.
Rulers everywhere sought to justify their rule but they varied in appealing to religions of different types, ancestors, martial valor etc. They likely built in an evolutionary fashion on perhaps small differences in preceding belief systems but there was some room for individual rulers to alter received beliefs. We thus see incredible diversity in how states justify their rule but a big similarity in that each state devotes considerable effort to doing so. (In regions such As Mesopotamia, competing states nevertheless shared a common religious pantheon which justified kingly authority.)
There were debates in early states about the advantages of codifying laws versus trusting judges. China with a larger bureaucracy than other states kept the emperor above the law over time. This early small difference in legal principles arguably had important effects on political development for centuries.
Gender stratification occurred in all states. Yet it occurred to different degrees in different societies. In some states, women could inherit, but in others they could not. The reasons for such differences are not always obvious.
Contingency: Highland New Guinea shows that agriculture does not necessarily lead to cities and states. Root crops other than the potato are too bulky to move long distances, and thus large states anywhere except South America relied on grain crops. Though some cities occupy natural harbors, there was contingency in the placement of others (evidenced by some cities declining and not being rebuilt, though this might sometimes reflect environmental changes). The precise timing of the decline of particular states might reflect a gradual (and universal?) process of bureaucrats and others usurping resources that would otherwise support the ruler but could also reflect a variety of highly contingent events such as there being no obvious heir for the ruler, climate shock, epidemic, lost battle, or a really bad ruler.
Some historians have argued that the particularly brutal rule of the Assyrians (the Jews were far from the only group they dispersed) resulted in them eventually not just being overthrown but no attempt ever being made to recreate their state: Can we posit that states that are particularly harsh are more likely to reach an ignoble end? If so, we would wonder why some states are harsher than others?
In hindsight many decisions to go to war seem ill-judged. Rulers who lost a war could lose their power and their life – and betray whatever justification of their state that they may have internalized. We must be careful here: a ruler might start a war simply to avoid being attacked by another at a time of their choosing. And wars are hard to predict: just because a ruler loses does not mean that they did not have good reason for thinking they might win. Still, it seems likely that the personality of rulers may loom large in decisions to go to war, and that states might often suffer because of ill-advised kingly decisions.
Writing systems differed.
5. The Classical Period
The period gets its name from the emergence of the classical empires. These empires were much larger than the early states we have discussed above. Empires will become the dominant form of political organization until the rise of the modern nation state in the modern era.
At the same time, we see the rise of what are commonly called missionary religions. It is one of the amazing features of world history that the vast majority of the world’s population to this day adheres to one of these religions.
Transformations: Empire itself (which reflect improvements in military and communications technology, as well as increases in agricultural output); new (generally universal and monotheist or deist) religions which can be seen as huge mutations to earlier mostly polytheistic religions. Empires did not found these new religions but over time found that the idea of one omnipotent god supported the idea of one omnipotent emperor (in turn the rise of emperors may have encouraged belief in one all-powerful god).
Trends: Population continues to increase, largely because of advances in agricultural productivity. Empires fostered an increase in trade that also raised incomes a little.
Evolutionary Processes: The new religions evolve from earlier religions. The main innovation is detailed ethical codes, generally enforced by an omniscient god that rewards good behavior (Deism in China also encouraged ethical principles). The new religions thus encourage social cohesion within large cities and empires. The new omnipotent gods maintained some of the human characteristics – notably being gendered – of previous polytheistic gods. The role of polytheistic gods is usually played in later religions by saints.
The new empires naturally borrowed some of the institutions and justifications of earlier states. One challenge was that empires were by definition multi-ethnic. They thus had to be justified with appeals to universal principles rather than ethnic loyalty. And bureaucracies had to navigate ethnic differences (this was a challenge in some earlier states but was a central challenge in empires). The general strategy was one of celebrating diversity: all that empires demanded was loyalty to the emperor. The early practice of absorbing the gods of conquered peoples into the pantheon became impossible as empires embraced monotheism (or deism).
Processes of technological and artistic evolution continue. Artistic evolution is encouraged by an elite class.
Culture: Some of the new religions would attract huge numbers of followers. They could thus serve as a force for cultural consolidation. Monotheistic (and deist) religions would over time displace polytheistic religions almost everywhere that they came in contact (sometimes but not always associated with military conquest). As noted above, monotheism made it impossible to absorb polytheistic gods of conquered peoples (though often these might find a place as saints within monotheistic faiths). Since each monotheistic faith proclaimed universal truths, there was often conflict among these. Most empires would come to favor just one religion – though there are numerous examples of empires that allowed multiple monotheistic faiths to coexist. The new religions could be an important source of conflict, but this was not always the case. [We could better understand the conditions under which the new religions could cohabit peacefully in history.]
In addition to conquest, the new religions were spread by merchants and missionaries. Both often sought to draw connections between existing beliefs and the new religions.
Population: Though the trend in population was upward, there were many epidemics spread by trade. The disruption associated with epidemics may have destroyed certain empires.
Social structure: Ethnic diversity was part of the definition of empire; empires generally accepted this but might try to draw elites into some shared sense of purpose. Conquered people saw advantages of adopting the language and customs of the emperor, so we tend to see some cultural consolidation.
The new religions generally served to entrench gender stratification. The new universal gods were male, and the priesthoods were generally dominated by males. Note that historical texts were often reinterpreted over time to limit the role of women [Islam and other religions may have sought to aid women by insisting on inheritance rights, but over time families responded by encouraging women to marry cousin so that inheritance stayed in the family.]
Slavery remained important in most if not all empires. Slavery likely encouraged political fragmentation on the borders of empire where “barbarians” warred for slaves.
Politics: Empires naturally meant much bigger bureaucracies. There were usually some formal efforts to educate bureaucrats.
Empires often employed different bureaucratic structures in different parts of the empire. Local laws were sometimes respected as long as these did not conflict with the laws of the empire.
Most if not all empires would expand geographically and later recede. This may reflect a tendency for generals to conquer lands that strained administrative capability. Once empires ceased to expand, they often struggled to replace the revenues previously gained from conquest: this then limited their ability to defend the frontier. Empires often entered into tribute relationships with peoples on their borders, and often hired them as mercenaries. Many empires would later be toppled by those that served the empire but maintained some independence. [Unforeseen consequences are common in history, and can be viewed as a kind of contingency in which people make decisions that actually hurt them or their descendants in the long run.]
The process of expansion and contraction often unfolded over a period of centuries. People far from the frontiers of empire might thus experience many generations of peace.
Empires built roads and harbors to facilitate bureaucracy and trade. Some empires stockpiled grain to prevent famine. Some managed irrigation systems. All operated legal systems. While there were thus some benefits to living in an empire, empires nevertheless employed force to maintain loyalty.
All empires struggled to maintain power against local elites and bureaucrats. Landowners grew in power over time in most/all empires. Empires often attempted land reform but were generally unsuccessful.
There were also religious bureaucracies. Though universal religions all proclaimed a holy book with the words of god, it turned out that these holy texts needed to be interpreted. And services needed to be performed, and temples funded. Empires would strive to control these religious bureaucracies with varying degrees of success. Religious bureaucracies turned out to be far from immune from problems of corruption.
Technology and Science: We have not mentioned science much before. States had long encouraged some sciences such as astronomy and medicine that might prove useful. Empires continued this practice. An independent science would emerge within Greek city states and these ideas would spread through the Eastern Hemisphere. Independent science did not usually prosper within empires.
We might also mention philosophy. This too prospered most noticeably in smaller states (in Greece and in China at a time of political fragmentation) but could sometimes prosper also under empire. The rise of philosophy reflected some of the forces driving the new religions: People sought guidance on how to live in a world of big cities and empires and trade.
The classical period has often been mistakenly viewed as a period of limited technological innovation. It is thought that the educated elite cared more about art and disdained practical activities, especially if these were associated with slaves. Yet there were important innovations in this period such as advances in both wind and watermills, and in shipping.
Economy: Empires encourage an expansion in trade, especially as they develop transport networks. Empires instituted common currencies. Incomes rose with trade, especially if empires achieved peace.
The new religions enhanced trust within trade networks, further reducing the cost of trade. Both Buddhism and Islam spoke at length about merchant practices, and Buddhist and later Islamic trade networks would operate throughout Eurasia and into Africa. Note that such merchants had a financial incentive to convert locals (and especially local rulers), though they may have been driven more by faith.
Empires may be the most unequal societies in human history. There is a small elite with great wealth. The middle class of merchants and artisans grows but remains small (some merchants become wealthy).
Art: Empires, universal religions and interregional trade all encouraged the spread of artistic ideas. Greek statues with Indian sensuality travel with Buddhism to China. Cave sculptures start in India but blossom in china
Environment: As noted above, empires improved transport networks almost everywhere. Yet the most dramatic “transport” improvement in this period was the Silk Road connecting China to the rest of the world: this was encouraged by the expansion of (especially the Han Chinese) empires, and facilitated by and other merchant networks.
Climate was very conducive when early empires were rising, but worsened later, and likely played a role in the decline of at least some empires.
Nomad incursions often reflected climate shocks. Yet their success depended on the development of nomad military technology such as stirrups (likely borrowed from China) and crossbows. The ability to form large tribal confederacies under charismatic leaders was also critical.
We noted in the previous period how geography shapes states, and stressed the role of natural barriers. As state size grows, Chinese states would repeatedly in history, starting with the Qin/Han, face mainly/only nomadic tribes on their borders. As with ancient Egypt, this had important effects on how Chinese rulers viewed themselves, and how intensely they developed military technology.
Recurring Patterns: Malthusian mechanisms continue to ensure that the main impact of innovations such as iron plows and watermills is on population size, though incomes advance a little.
Empires conquer many previously independent city states, but sometimes give local merchants some local power.
The fact that individual states rise and then fall is again dramatic but nevertheless a historical regularity. The growing power of local elites and landowners within states may also be a regularity, and an important source of decline.
Recurring challenges: Rulers face even greater challenges of controlling bureaucrats as empires grow in size. There are no really new strategies, except for using new religions to justify their rule.
The new religions are more important for merchants in both strengthening and extending merchant networks.
As noted above, nomads play an important role in trading with and warring with empires. The ability to form large tribal confederations is important for both defense and offence.
Priests gain much power and influence. Managing relationships with empires is critical, but also ensuring financial support from both empires and believers (but especially merchants).
Regions: Though we see empires (or at least very large states) on all inhabited continents during this period, the biggest empires (especially in terms of population) are in Eurasia. The size of states in the Americas is limited both by the lack of iron (and limited use of bronze) and by the absence of draft animals to pull either plows or wagons. African empires are also limited by low population densities and tropical diseases that were inhospitable to horses.
Though much of the world comes to be dominated by empires (and some other states), there are still lands dominated by hunter-gatherers, including much of North America. There are also large areas controlled by nomads in Eurasia. Nomads and empires often trade but sometimes fight with important consequences for both.
Empires themselves differed in administrative structures, institutions, treatment of ethnic groups, reliance on local elites, ideological justification, choice of religion, and more. The geographical environment could have an important effect on empires: empires in China could often have no other large state to face (but would battle with nomads), whereas empires in Europe, Persia, and India would often compete. India had limited iron, and needed to import horses, both of which created military challenges. Empires in the Americas and Africa were also at times able to dominate entire regions.
Yet we should also note many similarities across empires: all had bureaucracies, monumental capital cities, slaves, currencies, ideologies, laws, formal recognition of social hierarchies, massive income inequality, ceremonies that celebrated the empire, and more.
Though the Han Chinese empire would be reconstituted several times, Rome was not reconstituted because it was less obvious geographically, there was less legacy of centralized rule (due in part to less irrigation), and there was less development of cultural unity.
Each of the new religions that prospered received support from at least one empire (and some failed after this support ended). In some cases empires chose religions that had already achieved a popular following but in some cases empires faced options.
The present world distribution of religions reflects ruler choices about favored religion, decisions about toleration (but religions sometimes benefitted from conflict), conquest, missionaries, merchants, migrations, finance (some religions may have been better suited to nomads or merchants; nomads were important for geographical spread, merchants for financing temples and religious bureaucracies).
Contingency: There is considerable contingency in which empires chose which religions. The decision of the Kushans to embrace Buddhism was critical to the spread of that religion to China. The decision of the Guptas in India to embrace Hinduism would severely weaken Buddhism in its homeland.
There is considerable contingency in holy texts. Though these have all been reinterpreted through time, the words in holy texts can reverberate millennia later. The gender relations of the time influenced the texts, and those texts then influence gender relations thereafter. The fact that Islam was associated with military conquest from the onset means that its holy texts naturally talk about holy war more than the holy texts of other religions.
Since all of the new religions started small and grew through time, there is scope for a great deal of contingency. Manicheanism once was practiced from Spain to China but would largely die out when no large empire continued to support it. In the early Islamic conquests, there may have been important battles that might have gone the other way, but early successes drew many supporters to the cause (we might also note that both the Persian and Byzantine Empires were weakened at the time by wars with each other). As for Christianity, Constantine need not have chosen Christianity as the Roman religion.
6. The Middle Ages
We have sought in earlier sections to highlight both similarities and differences across regions. It becomes harder to identify broad similarities for the centuries immediately after the fall of the western Roman Empire. Western Europe is characterized by the decentralized political structure of feudalism; trade and incomes and urbanization contract with the fall of empire. China is characterized by a much less severe degree of political decentralization after the fall of the Han: several states generally compete for power. In between, Islamic, Byzantine, and other empires rule large areas. An alien visiting the planet in this period might have imagined that the future of the world would be dominated by these (especially Islamic) empires.
In the centuries after about 900 ce, it becomes far easier to identify commonalities:
Transformations: Among many technological innovations of this period we can single out the printing press. Though developed earlier in China, it would be in Europe that the printing press would dramatically lower the cost of publishing. This would in turn support an expansion in literacy, and the publication of numerous works of fiction and non-fiction. Though some rulers would be suspicious, printing presses would spread across Eurasia and into Africa.
Key trends: We see a process of political consolidation in most regions of the world during this period. This is generally accompanied by considerable cultural consolidation as locals adopt the cultural practices of the capital. (The printing press also supports some cultural consolidation so that all can read works published in the capital.)
Evolutionary processes: As in classical times, we can see an evolutionary process of both technological and aesthetic improvement in the monuments built in many societies (they often build taller over time, for example)
Cultural consolidation is itself an evolutionary process.
Institutional evolution continues, though it follows quite different paths in different regions (e.g. European feudalism changes over time)
Culture: As noted above, this is a period of cultural consolidation within states. It is also a period in which some of the practices of kingly courts diffuse into wider society.
Population: Population continues to expand across all regions much of the time. The global population likely increased from around 300 million in 1000 to 450-500 million in 1500. One notable change involves Polynesian migration far across the Pacific Ocean. With this migration, humans come to inhabit almost all lands that are inhabited today (the only exceptions being small settlements in extremely cold locations).
Another notable process is the expansion of agriculture into swamps and forests. This was often aided by the planting of crops imported from other regions. (Agricultural productivity also expanded with new rotations, transplanting crops between regions, and improvements in iron implements. Expanding trade opportunities encouraged farmers to grow more)
We have mentioned epidemics in previous time periods. The Black Death (bubonic plague) was one of the worst in human history, decimating populations from Europe to China – but having limited effects farther south. The plague would recur for centuries.
Social structure: In some societies, but not others, the plague resulted in an improvement in the relative incomes and social status of peasants by lowering the ratio of peasants to farmland. Some rulers used force to prevent peasants from bargaining for a better deal.
Politics: As noted above, this is a period of political consolidation almost everywhere.
As in the classical period, new states – and associated religions – celebrated their strength by building monuments.
Special mention should be made of the Mongol Empire which comes to control much of Eurasia. This greatly enhances the flow of trade and information of all types (in part as Mongols moved artisans around the empire). It also likely encouraged the spread of the bubonic plague.
Technology: We have celebrated the printing press above.
Economy: As noted above, the plague reduced income inequality in some lands. It likely also raised per capita incomes (the recurrence of the plague for centuries may have interfered with Malthusian mechanisms, though population did rise in most places in the long run)
Art: Though there is considerable artistic borrowing across regions, there are nevertheless large regional differences. Landscape painting becomes celebrated by the Song and later Chinese dynasties but has a limited impact on the rest of the world at this time.
Environment: The period from 900 to 1100 was unusually warm and wet, at least in Eurasia. This likely encouraged both population growth and political consolidation. The climate cooled around 1400. This may have encouraged Mongol conquests.
We noted above the geographic expansion of agriculture.
Recurring Patterns: We have seen that severe pandemics could limit Malthusian mechanisms, allowing incomes of the poor to rise in some places.
Though we have stressed a process of political consolidation, individual states nevertheless rise and fall as always. Later states tend to grow larger.
There is a great deal of mass migration in this period, especially out of Central Asia into Europe. Again, climate change may be an important cause.
Recurring challenges: The Mongol Empire could be harsh in conquest but thereafter fostered trade more than most empires. Merchants were encouraged in many ways.
Regions: Though there is political consolidation everywhere, the size of states still differs considerably across regions. This is partly due to the differing starting points. Yet the geographic constraints noted above continue to limit state size in the Americas and Africa.
Though monuments are built in most regions, they are of quite different styles: Gothic churches, pagodas, mosques, and more. There is nevertheless some architectural borrowing between societies so that there are similarities in arches between mosques and churches.
Contingency: As with Islamic conquests above, the Mongol conquests may have depended on some early victories that attracted new followers. Later, the Mongols were poised to invade Western Europe when an inheritance crisis caused the troops to return home. Western Europe might not have developed as it did if it had been conquered by Mongols.
7. The Early Modern Period
Transformations: The Columbian Exchange introduces new crops and diseases to all continents. It creates opportunities for imperial expansion, and spreads Christianity to the Americas. It encourages people everywhere to reflect on religious and philosophical questions. (It in turn reflects advances both in shipping technology and increased intercontinental trade. Though empires generally encourage trade, the rise of Islamic Empires appears to have encouraged a search for alternative routes between Europe and Asia.)
Advances in gunpowder technology lead to a revolution in military strategy and allow states with superior technology to conquer those without. This facilitates European conquests but also the rise of Ottoman, Safavid, and Mughal empires. Though gunpowder was originally invented in China, China would be slower to adopt gunpowder weapons.
Though empires continue to be important, this period also witnesses the rise of the nation state. This would become over the next centuries the dominant form of political organization in the world. Some nation states pursue democracy: this is something new in history since earlier democracies tended to be limited to small city states.
Late in the period the (British) Industrial Revolution will lead to modern economic growth: per capita incomes will expand in one state after another over the next centuries. Economic growth had never been sustained at such high levels for centuries previously. The Industrial Revolution also introduced factories (workers had often previously been gathered in one place for tasks like shipbuilding, but now tasks like textile production were also undertaken in large establishments), ushering in a world of large industrial cities.
Some would date the emergence of “capitalism” to this period, often without carefully defining the term. Merchants and trade have been around for millennia. Corporate forms of organizing economic activity become much more common in this period. Perhaps the greatest change in this period is cultural: a sense that profit-making and the pursuit of economic growth become dominant cultural attitudes.
We should also mention the scientific revolution – the emergence of communities of independent scientists that evaluate evidence for competing scientific propositions. This has some cultural influence at the time – influencing the Enlightenment, and questioning certain elements of religious doctrine. It may also have had an effect on the practice of technological innovators (encouraging, say, experimentation and careful recording of data), but a more direct influence of science on technology would not really happen until the nineteenth century (see below).
Key trends: The process of political consolidation continues across regions. Cultural consolidation continues also. Population continues to expand (despite unfavorable climatic conditions).
The trend of occupational specialization accelerates.
Evolutionary processes: This was a period of clarification of law codes. In China and Islamic states, a tradition of imperial control continued while in other parts of the world judges had more latitude to interpret laws. States competed (notably in Europe) to attract commerce through revisions to legal codes. Ideas were borrowed between states.
Technological innovation evolves a bit more rapidly than before, in some regions more than others. The Industrial Revolution at the end of the period is a historical inflection point with technology evolving much more rapidly thereafter.
Culture: There are notable examples of religious tolerance during this period by Ottoman and (most) Mughal rulers. Spain was at times characterized by tolerance and at other times not.
We should appreciate the cultural dislocation that occurred during this and later periods when quite different societies came in contact. Our cultures tell us how to behave, and how to expect others to behave (and provide an important source of meaning). The greatest dislocation occurs when technologically advanced societies contact less technologically sophisticated societies.
Population: Continued increase.
Social structure: The big change late in this period is the emergence of a large urban working class. Note that the earliest factories often employed women and children, and thus had an effect on gender relations (and family interactions).
We should also stress that most nation states pursue a policy of cultural consolidation: stressing a shared ethnic history (which downplays the interactions at the heart of world history), pursuing linguistic regularization, and developing shared celebrations. These efforts will intensify in the next period with public education. We should appreciate that the national identities of today were largely shaped over preceding centuries.
Politics: Political consolidation, legal codification. Colonization (very harsh treatment of indigenous peoples in most places), especially in the Americas.
Technology: Gunpowder is of huge importance. The Industrial Revolution will see dramatic changes in the production of textiles, various products made from iron, steel, and other metals, pottery and more.
Economy: Trade for the first time (excepting some Viking trips to Newfoundland, and some exchanges between Polynesia and South America) involves all continents. Late in the period we see factories begin to become important centers of industrial production. Corporations become an important form of commercial organization in some lands. The seeds of modern economic growth are planted.
Art: Cross-regional influences became far more important in this era, with artists almost everywhere borrowing ideas from other regions.
Environment: Temperatures were unusually cool in at least the northern hemisphere for most of the 15th through 19th centuries. The climate cooled even more in the mid-17th century: this may have encouraged political instability in many parts of the world (a temporary setback in the trend of centralization).
Recurring Patterns: Malthus formalizes his ideas late in this period, just decades before Malthusian dynamics cease to be dominant (first in some regions, eventually in all).
A trend of political consolidation is again associated with the rise and fall of individual states.
Recurring challenges: We introduce an important new agent here: the factory owner or industrialist. These need to supervise their workers. They need to ensure that workers have materials to work with. They need to sell a large quantity of goods (and thus some need to respond quickly to changes in fashion). As I argued in my dissertation and first book, they were aided immensely by improvements in the transport system in meeting these challenges.
As a result of formal education systems and printed books, the importance of formal apprenticeship systems in ensuring that the knowledge of artisans and builders is passed between generations declines – but there are still important things that can only be learned on the job.
Regions: Gunpowder begins to shift the relative balance of power between regions. The peoples of the Americas suffer colonization due to a combination of gunpowder and disease (there were also some fortuitous victories for Europeans early on when small expeditionary forces might have been wiped out despite superiority on weapons; losses there might only have delayed conquest). The flow of silver to Europe enriches Spain but arguably benefits other European countries more by fostering exports. Much of the silver ends up in China (reflecting the high price of silver in China as much as any Chinese disinterest in European goods).
Africa would likely have experienced more colonization (which might have in turn lessened the interest in transporting slaves to the Americas) if not for tropical diseases that limited European penetration. Tropical lands remain poorer and less densely populated on average during this period.
Contingency: Europe begins its rise to economic and political dominance during this period. It deserves to be stressed that this is not due to any huge advantage in European culture or environment, and certainly did not reflect any concerted plan on the part of Europeans: the Industrial Revolution was a surprise. It may in part reflect the fact that the Mongols never conquered Western Europe (we saw above that this was a highly contingent outcome) – Europe may have avoided authoritarian excess as a result (though it would later be very authoritarian in colonies). It may reflect the greater political fragmentation of Europe: this arguably fostered both military innovation and freedom of economic activity.
8. The Nineteenth and Twentieth Centuries
Transformations: Second Industrial Revolution, Totalitarianism, the (legal) end of slavery and serfdom, a dramatic change in gender relations in most places
Some political revolutions had huge impacts: the American, French, and Russian among them. The World Wars also can be considered transformative. The Great Depression?
Key trends: Population grows faster than ever before, but population growth rates tail off (in some countries before others) late in the period.
Incomes grow faster than ever before, but in some countries long before others.
The general historical trend of increased inequality within countries is reversed during the middle decades of the twentieth century but has since resumed.
One largely new but notable trend was an increase in the size of governments. States before 1800 had only rarely managed to tax more than 5% of total income. Over the next decades states came to tax 30 or 40% (sometimes more). They were able to tax more as incomes rose, and industrialization (and worker agitation) encouraged expenditures on education, health care, and a social safety net.
Trends in military conquest depend on how you treat the world wars: the succeeding decades have been peaceful in comparison at the global level, but some regions have experienced nasty wars since and the future is highly uncertain.
The trend of occupational specialization accelerates again.
Evolutionary processes: As bureaucracies grow in size, effort are made to regularize hiring, promotion, and other processes.
As the art market grows in size, artistic evolution accelerates. The global art market becomes big enough to support many competing (but mutually borrowing) art styles, whereas previous times and places tended to have one dominant style.
Cultural evolution also accelerates with increased global interaction and mass communications.
And of course the rate of technological innovation expands through most if not all of this period: We now expect frequent innovation.
There are many political revolutions during [the late 18th century and] this period. It can be argued that these are more likely to be judged successful if they try to change only a few things. The failures of many revolutions to achieve desirable changes tells us that humans are better in processes of evolutionary innovation than dramatic revolutionary change.
Culture: Some cultural practices, like western attire, become global. Others, like religious belief, change less, though agnosticism and atheism spread in many parts of the world.
Population: Mortality falls (especially child mortality) dramatically, at first due to better water and sewage systems in cities, in the twentieth century due to advances in medicine (and especially an understanding of germs).
Fertility falls even more (though usually with a lag of decades, resulting in temporarily large increases in population). This at first reflects urbanization, pension plans, and the increasing power within families of women. Improvements in birth control technologies become particularly important in the twentieth century.
We should also note a change in the location of population as most people come to live in cities.
And we should recognize massive migration flows in both centuries, though these change in direction.
Social structure: As women gained educational and employment opportunities they came also to exercise greater influence politically and within families. These changes influenced and reflected broader cultural changes in attitudes toward women. Though change occurred almost everywhere there were huge regional differences, partly due to differences in economies and sometimes due to stronger resistance from men in positions of power.
An even more dramatic transformation occurred with respect to slavery and serfdom. These practices would become illegal worldwide during this period (though illegal practices continue). These practices became less valuable economically with industrialization, but their eradication depended also on social condemnation. Still, owners of slaves/serfs were financially compensated if they were not defeated militarily.
Politics: The Industrial Revolution allowed the production of at first guns (including machine guns) and then complex machines like tanks and airplanes in large numbers. Industrial capacity became a huge determinant of military success, and wars became increasingly horrific.
The development of nuclear weapons raises the specter of a humanity-ending conflagration, but has steered the great powers to avoid direct military conflict.
Developments of industrial and communications technology made totalitarianism possible. States could now control everyday life in ways that earlier emperors could never achieve. Yet these same technologies also made democracy over large land areas feasible. Much of the political history of the period involves interactions between newish democracies and newish totalitarian states.
Much of Africa and Asia was colonized by European nations (and Japan) during the late nineteenth century. In the early postwar decades, most colonies in the world gain independence. This was an unusual historical occurrence: though there had been violent protests in many colonies, decolonization was encouraged also by many citizens of the colonizers.
Technology: The big event is the Second Industrial Revolution of the late nineteenth century. This involves big advances in chemicals, electricity, and internal combustion (some include advances in steelmaking). Almost every technological innovation since draws on at least one of these three elements of the Second Industrial Revolution. The Second Industrial Revolution in turn depends on the growth over preceding decades in the scale of industrial enterprises, and even moreso on a much greater reliance on scientific understanding. The technology of the First Industrial Revolution was developed by networks of independent innovators with a limited understanding of natural science; the technology of the Second Industrial Revolution was developed largely in industrial research laboratories filled with scientists and engineers.
We might make note also of the humble shipping container which dramatically lowers the cost of transport on both sea and land.
Economy: Rapid economic growth, first in a handful of European countries, eventually everywhere. Dramatic increase in cross-country differences in income and wealth (with some poor countries catching up more recently). Dramatic increase in trade.
The growth in both population and incomes was only possible because of changes in agriculture: new seeds, chemical fertilizers, and new machinery combined to dramatically increase yields. These advances occurred in some countries before others – with tropical countries seeing much less change (international agencies are financing research into increasing tropical yields).
Institutional experimentation with how to organize economic activity. A mix of private and public provision dominates, but with huge differences in degree.
Art: A global art market comes into being. Collectors and galleries buy art from all regions.
Environment: Climate change; reduced biodiversity
Rail networks; Road networks to handle automobiles; airports; huge ports to handle containers especially, Suez and Panama Canals
Human abilities: We have not spoken about these since the period of human evolution. There has been little genetic change during historical times (but some, such as development of lactose tolerance among most human societies). But there have been improvements in human abilities any time that human groups are able to eat more or avoid debilitating diseases. Such changes become much greater in this period. It deserves to be recognized that humans today live longer and are likely both stronger and smarter on average than ever before (though the move away from physical labor toward office jobs may limit advances in strength). [We are also better educated on average than before.]
Recurring Patterns: As noted in the previous period, Malthusian dynamics cease to dominate history in the nineteenth century. Economic growth starts to occur faster than population can expand, and so per capita incomes start to rise. This process starts in Europe but spreads to all continents during this period. Also, people restrict family size, allowing per capita incomes to rise even faster. The change in fertility decisions also starts in Europe but spreads to other parts of the world (It is still underway in parts of Africa and the Islamic world). It reflects how the costs versus benefits of having children change with urbanization (and pension plans), and also the increased power of women as these gain educational and employment opportunities.
Many new states emerge in this period, and many states suffer revolutions and coups. Will the states that have survived for centuries avoid the tendency of all states to rise and fall?
There are huge migration flows in both centuries, though these tend to involve individuals and families rather than entire tribal groups. Regional differences in incomes, job opportunities, and political systems drive most migration. Ethnic hostilities are sometimes important.
Recurring challenges: The factory owners introduced at the end of the last period become hugely important in this period. So also does a large urban working class. These often organize in unions which not only fight over wages and working conditions (with working hours falling toward 40 hours a week in many parts of the world but not much farther) but become politically active, pushing for voting rights in some countries and encouraging autocrats to introduce public health and education systems (which also served the interests of factory owners) in others.
As many countries introduce reliable systems of contract law, merchants become less dependent on networks (though enforcing contracts through the courts is no easy thing, and thus trust is still important).
Modern communications, accounting practices, and changes in cultural attitudes allow the emergence of modern professional bureaucracies. Though corruption still occurs, more in some countries than others, the challenge facing at least some rulers is less than ever before.
Regions: As the Industrial Revolution spreads slowly from one region to another, we see the greatest ever differences in average incomes or wealth across regions during this period. Recall that most people in most places had previously operated close to subsistence levels. Sluggish economic growth had not allowed any state to achieve per capita income levels more than two or three times that of another before 1800. But in the nineteenth century the richest countries could be twenty or thirty times richer than the poorest. There would be some catching up of some of the poorest (China, India, and others) in the twentieth and twenty-first centuries. But many African countries, despite experiencing some growth in per capita incomes, remain many times poorer than the richest countries in the world.
Democracy would also spread in the nineteenth and especially twentieth centuries, but has experienced some decline in recent decades. Conflicts, sometimes military, between democracies and autocratic regimes are not uncommon and cloud the future.
Despite huge differences in political organization and economic prosperity, there is a great deal of cultural sharing. Western clothing and movies and fast food becomes ubiquitous. Yet transmission occurs in all directions: you can find diverse cuisines in almost all countries. Singers from various countries gain global acclaim. It remains to be seen if such cultural exchanges can soften still-strong differences in religion and related cultural attitudes.
Note that tropical lands are still poorer than temperate lands on average, though the introduction of air conditioning, tropical medicines, and sometimes improved tropical crops can reduce this differential. Population densities have risen in many tropical areas.
Contingency: The results of the world wars may have been determined by the relative industrial potential of each side. Still, different outcomes can be imagined: say, if Germany had developed atomic weapons. The Russian Revolution might have turned out quite differently if certain key individuals had made different decisions (The rise of fascist dictators also seems to have hinged on certain contingent decisions). More recently, the deterioration of Russian democracy seems far from inevitable (though a centuries-long experience of authoritarianism in Russia likely contributed).