Robert of Mortain was the son of Herluin of Conteville and Herleva of Failaise; he had a younger brother, Odo of Bayeaux, and a half-brother, William of Normandy.
In 1066, in the French town of Lillebonne, roughly 25 miles east of Le Havre, a council was set up to discuss the invasion of England; at that meeting, Robert offered to provide 120 ships, toward the fleet, for which, on the success of the invasion, he was rewarded, by William, with the gift of 793 manors throughout England.
His reward gave him more land and possesions than those of any of the other followers of William. Of the 793 manors. there were 623 in the south-west counties of England, which brought him in £400 a year, 248 manors in Cornwall, 99 in Northamptonshire, 196 in Yorkshire, 75 in Devonshire (also included were a church and house in Exeter), 54 in Sussex, and the borough of Pevensey, 49 in Dorset, 29 in Buckinghamshire, and one or more in ten other counties.
He married Matilda, daughter of Roger of Montgomery - in 1082, with the guidance of their chaplain Vitalis, the abbot of Savigny, the couple founded a collegiate church in their castle of Mortain.
Robert died in 1091. and his son William succeeded him.
