First Aquitainian War (Chaos)

While the reason for OTL's Hundred-Year War (the French succession) didn't happen ITTL, the conflict between England and France had to come. In 1341, the broke out. supported Charles of Blois, John of Montfort - with the result that both were drawn into the war.

First half
In the Sea 1344, the English and Flemish defeated the French; England now ruled the Channel and could land troops in. 1345, entered the war against England, hoping to get the lost lands back. In 1346, the land took place in Brittany. Thanks to their longbows and the bad weather, the English defeated the French. In the same year, a great famine happened in Europe.

The, Aquitaine (50 km north of Bordeaux) in 1350 was another victory for the English.

In 1353, France had to make peace with England after the defeat in the. John of Montfort became duke of Brittany, England got all of Gascony (similar as in the peace of OTL 1360), acquired the. Free to make war against Scotland, the English defeat them soon, in 1354. The pre-war border was restored.

Second half
1366, went to France. In the same year, the French started the war against England again. Since they had learned how devastating the English / Welsh longbows were, they avoided open fight - with success.

Another big famine in Western Europe (1368) lead to growing unrest (again!) in France, which hampered the war against England.

In 1385, England and France made peace again. The English lost what they conquered in the last war, going back to the borders of 1340.

Aftermath
Since England still held a good part of Aquitaine, more wars would follow. The also didn't bring a decision, only after the  France succeeded in kicking England out.