The Hundred Years War can be divided up into three stages. This is due to lulls in the fighting where peace was discussed but later gave way to more fighting as the war continued in the 1400's.
The first phase would cover the period of 1337 to 1360 when the war first broke out. This phase concluded with England gaining control of more than half of France's territory and vassal states.
The second phase began in 1369 and lasted until 1389. It was during this phase that the newly crowned King of France Charles V managed push back the tide of England's territorial conquests as the war widened to include Spain and Portugal as well. This phase concluded with England having to sue for peace as internal issues took focus away from the wider war.
The third phase began in 1415 with the resumption of the war by Henry V. Henry managed to muster the English forces and defeat the French at Agincourt, winning the throne of France for his heir. Soon after his death in 1429, a peasant girl named Joan helped inspire the defeated French to counter-attack and by 1449 the French had retaken all of their territory with the exception of Normandy.