Complex sentence: Isabel and her sister, Constance, wife of Ellis de Beauchamp, had each inherited half the barony of Whitchurch from their father, and after the death of Constance, Isabel was heir to the entire barony of Whitchurch.
Split into simpler sentences: Isabel and her sister, Constance, wife of Ellis de Beauchamp, had each inherited half the barony of Whitchurch from their father. After the death of Constance, Isabel was heir to the entire barony of Whitchurch.