William Adelin, Duke of Normandy

William Adelin was born on 5 August 1103 in Winchester, Hampshire, England, to Henry I of England and Matilda of Scotland. As the heir apparent to the English throne, he was invested as Duke of Normandy during his father's lifetime. His marriage to Matilda of Anjou in June 1119 was part of a strategic alliance with Anjou.

William was closely involved in his father's affairs, receiving homage from the barons of Normandy and England. He was sometimes referred to as rex designatus, indicating his status as the designated king. His mother, Queen Matilda, served as regent in England, and after her death in 1118, William was old enough to take on similar responsibilities.

William Adelin died at the age of 17 in the White Ship tragedy on 25 November 1120 near Barfleur, Duchy of Normandy. His death without issue led to a succession crisis, known as The Anarchy, following his father's death in 1135.