William Adelin was a son of Henry I and Queen Matilda, and prince and heir to the English throne. He perished in the White Ship Disaster of 1120. William was the older brother of Empress Matilda “Maud” Beauclerc of Anjou, who took up his claim to the throne after he died. While his status as heir was apparently crucial to the unification of English, Scottish and Norman dynasties, it was well noted by scholars of the time that William was a prince so pampered he appeared tragically destined for disaster.
During the reign of William’s father, Henry I of England, King Louis VI of France expected Henry to pay homage to him as the Duke of Normandy. Unwilling to comply due to his preoccupation with domestic issues, Henry later invested William as the Duke of Normandy, although William took this on more as a title than a serious role.
After his mother’s death in 1118, William returned to England, then understood as the Rex Designatus (incumbent monarch). The following year, William married Matilda of Anjou to form an alliance between England and Anjou and subsequently moved there.
Returning to England from Normandy in 1120, he travelled on the doomed White Ship, which sank just off the coast of Normandy. This led to the death of William and around three hundred other passengers, including his half-sister and many members of the court. It is believed William could have survived the disaster, had he not been fatally swept away from his rescue boat while attempting to rescue other passengers.
Years after his death, it became known that William was an illegitimate child after his younger sister, Empress Maud, revealed herself to be a Hycatha. Since Hycathae can only produce daughters as long as they have their magical powers, it would have been impossible for William to be a biological son of Queen Matilda of Scotland. It’s widely accepted that William was indeed a biological son of Henry I by one of his mistresses, but passed off as a son of Matilda to ensure that the English crown would stay in the family.