William de Magnivil, corrupted into Mandeville, was keeper of the Tower of London. He m. Margaret, only dau. and heiress of Eudo de Rie Dapifer,* and had issue, Geoffrey and Beatrix. He was s. at his decease by his son, Geoffrey.
* Dapifer, id est, Steward, to King William for Normandy
[Sir Bernard Burke, Dormant, Abeyant, Forfeited and Extinct Peerages, Burke's Peerage, Ltd., London, England, 1883, p. 352, Mandeville, Earls of Essex]