The Hundred Years' War was a series of conflicts waged from 1337 to 1453 between the Kingdom of England and the Kingdom of France for control of the French throne. Many allies of both sides were also drawn into the conflict. The war had its roots in a dynastic disagreement dating back to the time of William the Conqueror, who became King of England in 1066 while retaining possession of the Duchy of Normandy in France. As the rulers of Normandy and other lands on the continent, the English kings owed feudal homage to the King of France. In 1337, Edward III of England refused to pay homage to Philip VI of France, leading the French King to claim confiscation of Edward's lands in Aquitaine.
Edward responded by declaring that he, not Philip, was the rightful King of France, a claim dating to 1328, when Edward's uncle, Charles IV of France, died without a direct male heir. Edward was the closest male relative of the dead king, as son of Isabella of France, daughter of Philip IV of France and sister of Charles IV. But instead, the dead king's cousin, Philip VI, the son of Philip IV's younger brother, Charles, Count of Valois, was crowned King of France in accordance with Salic law, which disqualified the succession of males descended through female lines. The question of legal succession to the French crown was central to the war over generations of English and French claimants.
The war is commonly divided into three phases separated by truces: the Edwardian Era War (1337â€“60), the Caroline War (1369â€“89) and the Lancastrian War (1415â€“53), which saw the slow decline of English fortunes after the appearance of Joan of Arc in 1429. Contemporary European conflicts directly related to this conflict were the War of the Breton Succession, the Castilian Civil War, the War of the Two Peters, and the 1383â€“85 Crisis. The term "Hundred Years' War" is a periodization invented later by historians to encompass all of these events.
The war owes its historical significance to multiple factors. Although primarily a dynastic conflict, the war gave impetus to ideas of French and English nationalism. Militarily, it saw the introduction of weapons and tactics that supplanted the feudal armies dominated by heavy cavalry. The first standing armies in Western Europe since the time of the Western Roman Empire were introduced for the war, thus changing the role of the peasantry. For all this, as well as for its duration, it is often viewed as one of the most significant conflicts in medieval warfare. With respect to the belligerents, English political forces over time came to oppose the costly venture; while English nobles' dissatisfactions, resulting from the loss of their continental landholdings, was a factor leading to the civil wars known as the Wars of the Roses. In France, civil wars, deadly epidemics, famines and bandit free companies of mercenaries reduced the population drastically.