Excerpts from Books and Wikipedia
"The war marked both the height of chivalry and its subsequent decline, and the development of strong national identities in both countries. Tensions between the crowns of France and England can be traced back to the origins of the English royal family itself, which was French (Norman, and later, Angevin) in origin. For this reason, English monarchs had historically held not only the English crown, but also titles and lands within France, the possession of which made them vassals to the kings of France. . . . French monarchs systematically sought to check the growth of English power, stripping away lands as the opportunity arose, particularly whenever England was at war with Scotland, an ally of France. . . . Several overwhelming English victories in the war—especially at Crécy, Poitiers, and Agincourt—raised the prospects of an ultimate English triumph, and convinced the English to continue pouring money and manpower into the war over many decades." Nobles in England became dissatisfied after losing their continental landholdings--a factor leading to the Wars of the Roses (1455-1487). [Wikipedia] War ended in 1453. "England's once vast territory in France is now reduced to only Calais, which they eventually lose control of as well." [Wikipedia: Timeline of Middle Ages]