“ His own rigorous government or the intrigues of Henry I. raised up against William a host of rebels; a rival claimant to Flanders appeared in the person of Thierry or Dirk of Alsace. In besieging Alost, one of the strongholds of the rival party, William received a wound which mortified and proved fatal (July 28, 1128) . He left no issue; although Duke Robert survived him and only died in 1134, the power of Henry I. was thenceforth undisputed by the Normans. ”