LESSON 2: How do historians organize time? 

Historians tell the story of the past in chronological order, which means events are told in the order they happen—first, second, third, and so on.

One way historians organize time is using the Gregorian timeline. On the Gregorian timeline, BC means Before Christ, and AD stands for Anno Domini, which means “in the year of the lord.”

Today, historians use a historical timeline, which uses different labels: BCE and CE. Historians prefer this timeline because it does not focus on a particular religion and is easier to use for studying history around the world. On the historical timeline, BCE means Before Common Era  and CE means Common Era.

How to Read Timelines:

We always read timelines from LEFT to RIGHT. This means BCE dates come before CE dates. Sometimes a date has c. or ca. in front of it. This means circa, or about / approximately. 

Historians look for turning points, which are events that cause big or important change. One turning point in ancient history was the discovery of fire, which helped early humans cook food and stay warm. Historians also divide history into eras, which are long periods with common characteristics. The Ice Age is an example of an era because it was a long time when the Earth was very cold and humans had to adapt to survive. 

Calculating Time:

• When two events have the SAME LABELS,  SUBTRACT.

• When two events have DIFFERENT LABELS, ADD. 

Other Resources for Unit 1:

• Holt textbook pages 6-31  (my.hrw.com)

  • Pages 6-9 Intro to History

  • Pages 7, 10, 11 Archaeology and Evidence

  • Pages 12-17 Geography Review

  • Pages 28-31 Archaeological discoveries and hominin characteristics