His possessions were increased following the defeat of Simon de Montfort at the Battle of Evesham (1265), via a series of grants that included the estates of the former rebel barons Walter de Fauconberg, John de Melsa and his brother Bernard. These grants were possibly compensation for the ransom his son Robert, negotiated and paid to his brother Bernard, and nephew Gilbert de Clare, 7th Earl of Gloucester, for his release following his capture, at the Battle of Lewes (1264). King Henry III also re-appointed Robert a Justice, and Constable of Carlisle Castle and keeper of the Castle there in 1267, a position he had been dismissed from in 1255. Robert sought pardon from Alexander and probably joined the princes Edward and Edmund on their crusade, as Robert if not Richard possibly failed to attend, or returned early, as the younger Robert is recorded as receiving a quitclaim in Writtle, Essex in October 1271