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
Henry I of England gave birth to a sequence of two sons, Henry and Geoffrey, in 1133 and 1134. Relations between Henry, Matilda, and Geoffrey became increasingly strained during the King's final years. Matilda and Geoffrey suspected that they lacked genuine support in England. In 1135 they urged Henry to hand over the royal castles in Normandy to Matilda whilst he was still alive, and insisted that the Norman nobility swear immediate allegiance to her, thereby giving the couple a more powerful position after Henry's death. Henry angrily declined to do so, probably out of concern that Geoffrey would try to seize power in