Guillaume Ier Crespin

Guillaume Ier was born about 1040.  Guillaume Ier's father was Gilbert Crespin and his mother was Gunnor De Courcy.  His maternal grandparents were Baudry Le Teutonique De Courcy and Alix De Clare. He had a sister named Hésilia.  He was the older of the two children.

They had a son named Guillaume II.