Middle Ages
Throughout the 14th century, French kings sought to expand their influence at the expense of the territorial holdings of the nobility. They ran into difficulties when attempting to confiscate the holdings of the English kings in southern France, leading to the Hundred Years' War, waged from 1337 to 1453. Early in the war the English under Edward III (r. 1327–77) and his son Edward, the Black Prince (d. 1376), won the battles of Crécy and Poitiers, captured the city of Calais, and won control of much of France. The resulting stresses almost caused the disintegration of the French kingdom during the early years of the war. In the early 15th century, France again came close to dissolving, but in the late 1420s the military successes of Joan of Arc (d. 1431) led to the victory of the French and the capture of the last English possessions in southern France in 1453. The price was high, as the population of France at the end of the Wars was likely half what it had been at the start of the conflict. Conversely, the Wars had a positive effect on English national identity, doing much to fuse the various local identities into a national English ideal. The conflict with France also helped create a national culture in England separate from French culture, which had previously been the dominant influence. The dominance of the English longbow began during early stages of the Hundred Years' War, and cannon appeared on the battlefield at Crécy in 1346.
House of Lancaster
Henry V of England was a successful and ruthless monarch. He was quick to re-assert the claim to the French throne he inherited from Edward III, continuing what was later called the Hundred Years' War. The war was not a formal, continuous conflict but a series of English raids and military expeditions from 1337 until 1453. There were six major royal expeditions; Henry himself led the fifth and sixth, but these were unlike the smaller, frequent, provincial campaigns. In Henry's first major campaignand the fifth major royal campaign of the warhe invaded France, captured Harfleur, made a chevauchée to Calais and won a near-total victory over the French at the Battle of Agincourt despite being outnumbered, outmanoeuvred and low on supplies. In his second campaign, he recaptured much of Normandy and in a treaty secured a marriage to Catherine of Valois. The terms of the Treaty of Troyes were that Henry's and Catherine's heirs would succeed to the throne of France. This condition was contested by the Dauphin and the momentum of the war changed. In 1421, Henry's brother Thomas, Duke of Clarence, was killed at the Battle of Baugé, and Henry V died of dysentery at Vincennes in 1422.