History of Bristol Welsh estate and Robert of Caen became the first Earl of Gloucester, c. 1122. He is believed to have been responsible for completing Bristol castle. In 1135 Henry I died and the Earl of Gloucester rallied to the support of his sister Matilda against Stephen of Blois who had seized the throne on Henry's death. Stephen attempted to lay siege to Robert at Bristol in 1138 but gave up the attempt as the castle appeared impregnable. When Stephen was captured in 1141 he was imprisoned in the castle, but when Robert was captured by Stephen's forces, Matilda was forced to
The Anarchy the spoils. William's son Henry I seized power after the death of his elder brother William Rufus and subsequently invaded and captured the Duchy of Normandy, controlled by his eldest brother Robert Curthose, defeating Robert's army at the Battle of Tinchebray. Henry intended for his lands to be inherited by his only legitimate son, seventeen-year-old William Adelin. In 1120, the political landscape changed dramatically when the "White Ship" sank en route from Barfleur in Normandy to England; around three hundred passengers died, including Adelin. With Adelin dead, the inheritance to the English throne was thrown into doubt. Rules of succession