William FitzSulgwen (born 1105) was an illegitimate son of Henry I of England. In 1137 he plotted an attack against King Stephen of England, his cousin, to claim the throne, but he was defeated and died in the deepest pit in Stephen's dungeon.
Biography[]
William was born in 1105, the illegitimate son of Henry I of England. He became a courtier in the County of Tarragona after his father's death, living in exile as his father's nephew Stephen of England succeeded him due to Henry lacking any legitimate heirs. On 2 August 1137 William began recruiting an army of mercenaries to enforce his claim to the Kingdom of England from his base in Spain. Stephen recruited Count Roger of Tarragona, Countess Agnes of Tarragona, Maurice FitzGerald, Alfons, Baron Bohemond of Sant Cugat, William de Windsor, Hugh de Morville, and Busilla in a plot to assassinate William and end his threat.