He paid homage to King Philip I of France for these estates and sat as a French Peer in the Parliament held at Poissy.
Robert and his brother Henry were members of the Royal hunting party in the New Forest in Hampshire when King William II Rufus (1087–1100) was shot dead accidentally by an arrow on 2 August 1100.
During the English phase of the Investiture Controversy, he was excommunicated by Pope Paschal II on 26 March 1105 for advising King Henry to continue selecting the bishops of his realm in opposition to the canons of the church.
According to Henry of Huntingdon, Robert died of shame after "a certain earl carried off the lady he had espoused, either by some intrigue or by force and stratagem.
He and Elizabeth had the following progeny: Robert De Beaumont is portrayed by Jotham Annan in the 3 part BBC drama-documentary presented by Dan Snow, 1066: A Year to Conquer England.