Robert of Mortain
Norman nobleman and the uterine half-brother of William the Conqueror
Robert (c. 1031–c. 1095), count of Mortain and earl of Cornwall, was a Norman nobleman and the maternal half-brother of King William the Conqueror of England. He was one of the very few proven companions of William the Conqueror at the Battle of Hastings in 1066, and as recorded in the Domesday Book of 1086 was one of the greatest landholders in his half-brother's new Kingdom of England.
Life
Robert was the son of Herluin de Conteville and Herleva of Falaise and brother of Odo of Bayeux. Robert was born c. 1031 in Normandy, a half-brother of William the Conqueror. and was probably not more than a year or so younger than his brother Odo, born c. 1030. About 1035, Herluin, as Vicomte of Conteville, along with his wife Herleva and Robert, founded Grestain Abbey in Normandy.
Count of Mortain
Around 1049 his brother Duke William made him Count of Mortain, in place of William Werlenc, who had been banished by Duke William; according to Orderic Vitalis, on a single word. William Werlenc was a grandson of Duke Richard I and therefore a cousin once removed to William, Duke of Normandy. Securing the southern border of Normandy was critical to Duke William and Robert was entrusted with this key county which guarded the borders of Brittany and Bellême.
Conquest of England
In early 1066, Robert was present at both the first Council of Lillebonne, that of William's inner circle, and the second larger council held to discuss the Duke's planned conquest of England.
Begin with the source’s own compact description: “Robert of Mortain” is norman nobleman and the uterine half-brother of William the Conqueror. The dossier treats that line as a proposition to test through Robert, Mortain and Norman, not as a finished interpretation.
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Named sources, stable identifiers and responsible institutions provide the strongest route from overview to verifiable evidence. The source revision retrieved here is dated Jul 17, 2026. The linked authority identifier is Q724235. VIAF identifies the subject as 4319711. The Library of Congress control number is n2004022227. 2 of 3 selected statements include explicit references; 1 carry qualifiers and 0 use preferred rank. The first chronological checks are 1031, 1095, 1066 and 1086.
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This entry incorporates text from “Robert of Mortain” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.