However, according to Round (died 1928) "no proof exists that Richard I de Grenville ever held the manor of Bideford, which was later one of the principal seats of the Westcountry Grenville family. It was however certainly one of the constituent manors of the Honour of Gloucester granted by King William Rufus to Robert FitzHamon." Richard de Grenville is known to have held seven knight's fees from the Honour of Gloucester, either granted to him by his brother FitzHamon or the latter's son-in-law and heir Robert, 1st Earl of Gloucester (1100–1147). Round supposes instead that the Grenvilles of Bideford and Stowe were descended from a certain "Robert de Grenville" ("alias" de Grainville, de Grainavilla, etc.) who was a junior witness to Richard's foundation charter of Neath Abbey, and who in the 1166 Cartae Baronum return was listed as holding one knight's fee from the Earl of Gloucester, feudal baron of Gloucester. Robert's familial relationship, if any, to Richard is unknown.