How much of France could England have retained from the Hundred Years War?

It depends on what the Kingdom of France is like in your scenario. Is it still going to be like OTL and have its kings progressively extend their royal power over the centuries? If so, I think it's an all-or-nothing affair for England. It can possibly seize the throne of France and rule it all, or it will lose everything as in OTL, because defending individual territories on French soil would be exceedingly difficult as time went on. France in the Hundred Years' War had four times the population of England. When its royal authority was weak and the nobles (like the dukes of Burgundy) revolted, England could hang on to its territory, but when France was united (as it was from 1435 onward) England did not have the resources to defend its French territory indefinitely.
 
To be honest, HYW wasn't really winnable for England, assuming we understood union of the crown as the objective of the war.

At worst, it would have turned into a war of attrition, and while France had really divided periods up to civil war, it beneficied from quite ressources (demographic, economics, military, etc.) that England did catched up but with a Parliment not too enthuiast about it.

At best, Plantagenets or Lancasters could keep a good portion of France (and far more likely in the south than in north) but still risks the usual issues : local nobles asking for help to French kings, badly united demesnes, more important ressources in French side, etc.

Would England be able to hold Aquitaine/Guyenne? I don't think it would be possible on the long run : each time the kingdom of France managed to get its shit together during HYW, it managed to win what was basically a war of attrition. But it could hold at least long enough to crave some sort of equivalent to Pale of Calais that could be maintained longer than Aquitaine per se.

There's a reason why the war lasted decades, or why Plantagenets preferred to make truce and peace of compromise as Brétigny as more realistic objectives while they clearly had the upper hand.
 
I don't see why it couldn't be 100% (of France as it was, 100% of France we know it wasn't united by France until much much later) if England gets a succession of very good leaders and France a succession of terrible leaders.
The trouble is that situation would be like the union of Scotland and England- the monarchs may have been far more Scottish to begin with....but England was by far the richer and more important throne.
Substitute England for Scotland and France for England et voila.
 
Forget about "England" This was not England buy the dynasty reigning in England. Which was basically a french dynasty.

How much can the king of England retain in France ? Almost nothing except a few fortified places like Calais. They can keep territories only as long as the rival dynast ruling in France decides not to take it back. Or your are going to need the king of England to have permanent armies to preserve his holdings in France.

What the king of England needs is what he missed : being accepted as the legitimate king of France. This is the only way for him to stand in France.

The best opportunity would have been Philip IV of France live 15 more years and chose his grandson Edward III as his heir.
 
@ Matteo: I very much doubt that Philip IV would do that. Since he would most likely remarry after the death of Joan of Navarra, probably to a young princess from an important noble house.

Not to mention that most in France, including the large and prominent Capetian clan (to include every branch) will be death set against that.
 
Top