He and Hugh 4001 were the only crusader counts who were the children of kings, and so in the battle against Kerbogha 4001 it was fitting that they should lead the first two divisions
nobilis eques de exercitu comitis Normannorum. William of Tyre bk. 3, 10(9).28-29
In his own land, he was too lenient a ruler who allowed far too much disorder by not punishing the guilty, and he had a most luxurious lifestyle; these traits were not obvious on the crusade
Ralph of Caen 15
Most savage in military weapons and very rich in property
ferocissimus armis militaribus et rebus ditissimus. Albert of Aachen II.22
Son of King William of England
Willelmi Anglorum regis filius. William of Tyre bk. 1, 17.5
As one of the main commanders of the crusader army, he was also (with Hugh 4001 and Robert 62) the leader of its first line of attack against Kerbogha 4001