Geoffrey I MORTAGNE 
Geoffrey I was born about 1015 in France. Geoffrey I's father was Warin MONTAGNE and his mother was Melisende CHATEAUDUN. His paternal grandfather was William ALENCON; his maternal grandparents were Hugh CHATEAUDUN and Hildegarde de BLOIS. He was an only child. He died after December 15th, 1031.
They had a son named Rotrou I.