Sister of Grimald de was born about 1014 in Plessis, Normandy, France. Sister of Grimald de's father was Grimolt de Plessis. She was an only child. Sister of Grimald de is no longer alive.
‌Sister of Grimald de and William d' were married in a religious ceremony before 1048. They had a son and two daughters, named Roger d', Oliva d' and Aimee d'.