MILITARY CAMPAIGNS IN THE fifteenth century were characterised by wars with the traditional enemies of England, principally France and Scotland, as well as with rebellious subjects. The long running conflict with France known as the Hundred Years’ War began in 1337 with the attempted confiscation of the duchy of Aquitaine by the French king Philip VI. Three years later, in 1340, Edward III asserted his claim to the French throne which, despite being given up at the Treaty of Brétigny in 1360, was also claimed by his successors. Henry V asserted this right to the French throne in 1415 and launched his first invasion of France. As a result of his military victories, including the conquest of much of Normandy from 1417 to 1419, he was able to negotiate the Treaty of Troyes with Charles VI in 1420, which recognised him as the latter's heir, but he died in 1422 before becoming king. He was succeeded by his infant son Henry VI, with the conduct of the war against the supporters of the Dauphin, later Charles VII of France, directed by the young Henry's uncles, the dukes of Bedford and Gloucester. Henry VI was crowned king of France in 1431 but the French were later able to drive the English out of all of their lands in France, with the exception of the Pale of Calais, by 1453. The loss of almost all of England's Continental possessions did not end Anglo-French hostilities, however, with major expeditions being sent to France in the reigns of Edward IV and Henry VII. The Franco-Scottish alliance, known as the Auld Alliance, meant that conflict between England and Scotland was also linked to war with France. For much of the century, hostilities largely took the form of limited cross-border raids, but large English armies invaded Scotland in 1400, 1482 and 1497.

The political instability which resulted from Henry Bolingbroke's usurpation of the throne in 1399 meant that the fifteenth century was also defined by rebellions and civil war. Henry IV was forced to contend with major uprisings in Wales, led by Owain Glyndŵr, and in the north of England, led by the powerful Percy family.