Claim: Henry III assumed the throne when he was 9 years old in 1246.
Evidence: The son of King John and Isabella of Angoulême , Henry assumed the throne when he was only nine in the middle of the First Barons ' War.
Henry III -LRB- 1 October 1207 -- 16 November 1272 -RRB- , also known as Henry of Winchester , was King of England , Lord of Ireland and Duke of Aquitaine from 1216 until his death.