William D'Avranches was the son of Simon D'Avranches and Cecilia, daughter of ----- Criol. He defended the castle of Rochester against King John and was Constable of Dover Castle in 1225. He married Maud or Mabel, daughter and co-heir of John Bovil. For her descent see bottom of this page.
Simon D'Avranches was the son of William D'Avranches, Lord of Folkestone and Maud, daughter and co-heir of William de Bocland and Maud, daughter and co-heir of William de Say.
William D'Avranches was the son of Rualon D'Avranches, son and heir of William, sheriff of Kent in 1190. He married Maud, the only daughter and heir of Nigel de Monville, Lord of Folkestone.
Nigel de Monville was the son of Ralph de Monville, Lord of Folkestone. He married Emma, the 2nd daughter and co-heir of William D'Arques.
William D'Arques held Folkestone under Odo, Bishop of Bayeux, 1086. He married Beatrice the daughter of Geoffrey de Bolbec.
Geoffrey de Bolbec married Beatrice de Gozelin.