Complex sentence: The Patriach's name is disputed, the Romance gives the name of Warin de Metz, came to England during the reign of William the Conqueror, but neither he nor his sons held any land in chief during that time.
Split into simpler sentences: The Patriach's name is disputed, the "Romance" gives the name of Warin de Metz. It is generally believed that the head of the Warin family came to England during the reign of William the Conqueror, but neither the father nor his sons held any land in chief during that time.