He was the son and successor of John as King of England, reigning for 56 years from 1216 until his death. His contemporaries knew him as Henry of Winchester. He was the first child king in England since the reign of Æthelred the Unready. England prospered during his reign and his greatest monument is Westminster, which he made the seat of his government and where he expanded the abbey as a shrine to Edward the Confessor. He is the first of only five monarchs to rule the Kingdom of England or its successor states for 50 years or more, the others being Edward III (1327-1377), George III (1760–-820), Queen Victoria (1837-1901) and Elizabeth II (1952–present).
He assumed the crown under the regency of the popular William Marshal, 1st Earl of Pembroke, but the England he inherited had undergone several drastic changes in the reign of his father. He spent much of his reign fighting the barons over Magna Carta[ and the royal rights, and was eventually forced to call the first "parliament" in 1264. He was also unsuccessful on the Continent, where he endeavoured to re-establish English control over Normandy, Anjou, and Aquitaine. Henry was pious and his journeys were often delayed by his insistence on hearing Mass several times a day. He took so long to arrive for a visit to the French court that his brother-in-law, King Louis IX of France, banned priests from Henry's route. On one occasion, as related by Roger of Wendover, when King Henry met with papal prelates, he said, "If [the prelates] knew how much I, in my reverence of God, am afraid of them and how unwilling I am to offend them, they would trample on me as on an old and worn-out shoe." Henry III, Treasures in full: Magna Carta, British Library Given-Wilson, Chris (1996). An Illustrated History of Late Medieval England. Manchester University Press, Manchester. p. 87 Plantagenet ancestry: a study in colonial and medieval families, by Douglas Richardson and Kimball G. Everingham
Buried at Westminster Abbey