Henry was one of five sons of Stephen II, Count of Blois, by Adela of Normandy (daughter of William the Conqueror) and the younger brother of King Stephen. His birth date is uncertain, along with his siblings but he was the 4th or youngest son and he was most likely born at Blois c.1096, before his father left on the first crusade, or possibly c.1100, soon after his father's return. Henry's father died in 1102 while on crusade during the Second Battle of Ramla, leaving an estate with more than 350 castles and large properties in France including Chartres.