In 1247, William X died and Robert inherited the county of Auvergne.[1] His mother remarried with Arnold II of Wezemaal.[1] The two guaranteed Robert that they would not demand any of the possessions he inherited from his father.[3]
In 1245, Robert married Èleonore of Baffie,[5] daughter of William "the Elder" of Baffie and his wife, whose name is unknown.[6] They had six children:
Godfrey († 1302), who was started on the ecclesiastical path, but after finishing his studies, left the church and later died in the Battle of the Golden Spurs.[6]