The Treaty of Windsor is the diplomatic alliance signed between the Kingdoms of Portugal and England in 1386 at Windsor and sealed by the marriage of King John I of Portugal from House Aviz to Phillipa from House Lancaster. After the victory of Aljubarrota, John I was recognized as the undisputed King of Portugal, putting an end to the interregnum crisis of 1383-1385. 

511 - King Clovis I dies. He tamed Gaul and conquered and united all the Frankish tribes, becomes King of the Franks, and converts to Catholic, he converts most of the French and west German region to Catholic. "France" hereby gets the title of "Eldest daughter of the Church" by the papacy.

597 - Augustine, a monk from Italy lands in Canterbury (Kent eu4 province in England) from where he begins to missionary and converts lots of Britain clay.

732 - Battle of Tours, The Umayyad Caliphate invades through Iberia and loses in Tours (Touraine eu4 province) to Charles Martel. France and West-Germany becomes disunited and is reunited again under Charlemagne.

793 - England is made up of small Catholic Kingdoms with infighting until now, when the Scandinavian Vikings raid Lindisfarne and the Viking age becomes a big thing.

800 - Charlemagne becomes the first HRE.

843 – The Empire is split into East Francia, Middle Francia and West Francia. West Francia is almost the same region as modern France.

875 – Vikings conquer East Anglia, Mercia and Northumbria. The Vikings lose battles to Alfred of Wessex and is “contained” within a region he calls the Danelaw.

950 – English Kings expands into the Danelaw and retakes York. The West Saxon rulers call themselves Kings of the Angelcynn, that is all the English people.

843-918 West Francie gets raided insanely in this period. The French King allows Vikings to settle in the North to peace them.

918 - Viking Rollo from Scandinavia becomes Count of Rouen and rules Normandy.

987 – King Louis V of France the “Do-Nothing” dies in a hunting accident as the last of the Carolingian dynasty. The nobles of West Francia elects Hugh to the next King. This begins the dynastic line of House Capet.

1066 – Massive succession crisis in England under King Edward the Confessor.

1066 – William, the Duke of Normandy and descendant of Rollo, takes advantage of the English Crisis and invades England. He becomes King of England Christmas Day the same year.

This is the point in which England and France gets their noble houses intertwined and the messy parts begin.

1120 – William Adelin, the only heir to England drowns in the sinking of White Ship. With no male heir, King Henry I names his oldest daughter Matilda as his heir. Matilda is at this point married to Henry V the Holy Roman Emperor, making her an excellent choice.

1135 – King Henry I dies. His heir Empress Matilda, the widow of the Emperor, has now married Geoffrey Plantagenet, a noble house that he started, that becomes one of the most important noble houses in English history.

1138 - The nephew of King Henry I, Stephen of Blois and Duke of Normandy rivals his cousin Matilda and makes a coup d’etat and crowns himself King of England. England enters a civil war known as ‘The Anarchy’.

1154 – The Anarchy ends with the Treaty of Wallingford, which keeps Stephen as the King of England, but the heir to the throne becomes Empress Matilda’s son, Henry II of England from House Anjou/Plantagenet. He is married to Eleanor of Aquitaine, the divorced wife of Louis VII of France.

This is a messy part, as a royal house of French origin rules England and large portions of French region lands through marriage. This is the period known modernly as the ‘Angevin Empire’ consisting of England, Aquitaine, Brittany, Normandy, Anjou, Gatinais, Maine, Touraine and Mortain.

1159 – The beginning of the Capet-Plantagenet Rivalry. The kings of West Francia and the Angevin Empire has a series of wars and clashes with the goal of The French King to suppress the growing power of the Plantagenet dynasty. Important factors regarding this rivalry is 1. Both dynasties are French in origin. 2. The nobles dominating the English court and domineering the French King were French noble houses. 3. The vast majority of the English army were local recruits of French culture.

1180 – King Philip II of West Francia uses the term King of France instead and begins a massive military campaign against the English King.

A conflict between House Plantagenet and House Valois. The period is usually divided into different phases separated by smaller truces.

1337-1360 Edwardian War

England fights only with their vassals, the French is supported by Scotland, Genoa, Bohemia, Lorraine, Navarre and Castile. Edward III of England and his son Edward The Black Prince leads their armies personally and they dominates the initial phases of the wars. There is a brief peace period in 1350 because of the plague, in 1356 at the battle of Poitiers, the King John II of France is captured and in 1360 the Treaty of Bretigny is signed, after the ransom of John II. This treaty grants England lots of new clay.

https://en.wikipedia.org/wiki/Treaty_of_Br%C3%A9tigny#/media/File:Map-_France_at_the_Treaty_of_Bretigny.jpg

1369-1389 the Caroline War

The Black Prince, the heir to the English throne, spend a huge sum of money to restore Pedro of house Ivrea to the Castilian throne. Pedro became known as ‘The Cruel’ for his crimes against the clergy which led to his excommunication. Pedro was unable to repay the English, so Edward the Black Prince heavily taxed the Aquitaine lands. The people of the land complained unheeded, so they asked for help and liberation of King Charles V of France. Charles V demanded to see The Black Prince in Paris to negotiate a treaty to deal with the crisis in Aquitaine, when it was refused and Edward did not show up, Charles invaded with the goal to liberate the French people.

Shortly after the invasion began, Edward The Black Prince leaves Aquitaine in start of 1370 for London, as his health began to worsen. He dies in 1376 and his son Richard, becomes the new heir to the throne, and becomes Richard II of house Plantagenet becomes King of England in 1377, at the age of 10. Charles VI becomes king of France in 1382.

They sign the Truce of Leulinghem in 1389. England is on brink of economic collapse and suffering from internal political division. France is suffering from Charles VI mental illness that handicapped the French government.

Neither side was willing to concede the cause of the war, the duchy of Aquitaine. But peace was desperately needed by both sides of the war, so they agreed upon a truce, which contained three important parts

1.  Joint crusade against the Turks in the Balkans.

2.  Marriage between Richard II of England and Charles VI daughter, Isabella of Valois.

3.  Peace until 1416, when new negotiations would occur.

The goal of the marriage was to hope for more stability and peace between the nations, but we all know how it goes. What is important is, that Richard II is mentally unstable, just as the French King. Richard has no children and after a period of unrest due to his mental status, he abdicates the throne to one of his close relatives, Henry of House Lancaster, the cadet branch of House Plantagenet.

Lots of interesting things happens between this part and the next part in the war, but they will only make the list longer and too complicated, but they can be read about, or I can find some focus points for the interested.

1415-1453 the Lancastrian War

The Truce of Leulinghem was written in 1389 and Henry IV of England becomes king in 1399. The English king is in poor health, but regardless manages to have lots of children. He dies at age 33 and his son and heir, Henry becomes king at age 27 in year 1413. This part of the war is called the Lancastrian War, as the English throne now is ruled by House Lancaster.

1414, France is still dominated by Charles VI unstable mental state, which lead to his nickname ‘The Mad’. Since his rule began in 1380, things has now in 1414 escalated into civil war between the Burgundian faction and the Armagnac faction.

King Henry V proposes a deal to the civil war and insanity dominated French Kingdom. He demands the French throne, the restoration of the Angevin Empire and one of Charles VI’s many daughters in marriage. If they demands are not met, he will invade and take the French Throne and secure peace and stability through his great-grandfather Edward III’s claim to the French Kingdom.

1415, august, Henry V invades France. The invasion is initially slow as they besiege the city of Harfleur, it took five weeks and disease on both sides for the city to surrender. The army was in such a bad shape that they marched north to Calais back to English territory to sharpen up.

Agincourt - On their war to Calais, they have to cross the river Somme, but once they reached it, their scouts figured out that a massive French army guarded the river crossings. Henry commanded his army to go west along the river and find another crossing. They were low on supplies as they were expected to be in Calais shortly after. The large French army came as a surprise and it took several days on low supplies to find an unguarded area to cross, once they did, they were found by the French, that moved in on the outnumbered English army. This results in the legendary battle of Agincourt were English longbowmen and the use of terrain lead to the French army being completely decimated 

This turned the tide of the war towards the English that again and again won engagements and began to dominate large areas of land.

Treaty of Troyes – France is desperate and ruled by the Insane King Charles VI. Henry

It ends in 1453 with victory for the House of Valois that keeps France united, and England loses all continental land except Calais.