Upon his accession to the throne, Henry dismissed the incumbent ministers and made Henry Beaufort lord chancellor. A rebellion by the Lollards, led by Sir John Oldcastle, resulted in a strong parliamentary statute (1414) against the sect, but trouble continued intermittently until the execution of Oldcastle in 1417. Determined to regain the lands in France held by his ancestors, Henry arranged a secret pact with Burgundy and prepared to attack France, thus reopening the Hundred Years War. Launching his first invasion in 1415, he laid successful siege to Harfleur and marched toward Calais, having announced his claim to the throne of France. He met and defeated a superior French force in one of the most famous battles of English history at Agincourt (1415).
The enthusiastic acclaim that Henry received for this victory for the time overshadowed English political and economic unrest. Henry formed (1416) an alliance with Holy Roman Emperor Sigismund and extended his agreement with the Burgundians. In 1417 he led another expedition to France. In 1419, Rouen capitulated, and Normandy was in English hands. In 1420, Henry concluded the Treaty of Troyes, by which he agreed to marry Catherine of Valois and to rule France in the name of her father, Charles VI, who accepted Henry as his successor.
The English king continued his conquests to consolidate his holdings and late in 1420 entered Paris. The following year he returned with his wife to England, there made further military preparations despite considerable popular opposition to the continuation of war, and embarked on his third invasion of France. After a year of minor victories, he fell ill and died in Sept., 1422.
The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.