Robert Count of Mortain

Robert, Count of Mortain, 2nd Earl of Cornwall (c. 1031–c. 1090) was a Norman nobleman and the half-brother (on his mother's side) of King William The Conqueror. He was one of the very few proven companions of William the Conqueror at the Battle of Hastings and as recorded in the Domesday Book of 1086 was one of the greatest landholders in his half-brother's new Kingdom of England.
Credit: Wikipedia