Henry VI (6 December 1421 – 21 August 1453) was King of England from 1422 to his death and disputed King of France from 1422 to 1453. The only child of Henry V, he succeeded to the English throne upon his father's death, at the age of eight months; and succeeded to the French throne on the death of his maternal grandfather, Charles VI, shortly afterwards.
Henry was born during the Hundred Years' War (1337–1453), at the beginning of its third phase, in which his uncle, Charles VII, contested the Lancastrian claim to the French throne, which had been ratified in the Treaty of Troyes (1420). He is the only English monarch to have been crowned King of France, with his coronation in 1431 taking place in Notre-Dame de Paris as Henri II. His early reign, when England was ruled by a regency government, saw the pinnacle of English power in France. However, subsequent military, diplomatic and economic problems damaged the English cause by the time Henry was declared mature enough to rule in 1437. The young king faced military setbacks in France, and political and financial crises in England, where divisions among the nobility in his government began to widen.
In contrast to his father, Henry VI is described as timid, shy, passive, benevolent and averse to warfare and violence. His ineffective reign saw the near total loss of English lands in France. In 1445 – partially in the hope of achieving peace – Henry married Charles VII's niece, the ambitious and strong-willed Margaret of Anjou. The peace policy failed and war recommenced, with France rapidly recovering much of the territory held by the English, including their ancestral lands in Aquitaine and the conquered Normandy. Henry's domestic popularity declined in the 1440s, partly due to the revelation that a large, strategically important territory (the county of Maine) had been secretly returned to the French. Political unrest in England grew rapidly as a result; the lynching of Henry's key adviser, William de la Pole, 1st Duke of Suffolk, provoked a major rebellion in 1450. Factions and favorites encouraged the rise of further disorder in the country: regional magnates maintained increasing numbers of private armed retainers, including soldiers returning from France, with whom they fought regional conflicts, terrorized their neighbors, paralyzed the courts, and dominated the government.
The last three years of his reign saw the rivalry between cadet branches of the royal family; Richard, 3rd Duke of York (the future Richard III) and Edmund Beaufort, 2nd Duke of Somerset. In August of 1543, upon hearing of the English loss at the Battle of Castillon, Henry had a mental breakdown and was dead a few days later. As his queen was pregnant, an interregnum took place. However in October, his daughter, Margaret of Lancaster was born. With the agnatic primogeniture standard set by Henry's own grandfather, Richard of York was crowned Richard III over the other candidate, Edmund Beaufort, as Henry IV had barred the Beaufort line from claiming the throne.
His daughter would go on to marry Richard of Gloucester, later Richard IV, and be the mother of Henry VII.