The Campbells gave support to the Crown throughout the 15th century. By the end of the 15th century the power of the Lords of the Isles (chiefs of Clan Donald) who were the Crown's most powerful rivals had been broken leaving the Campbells as the main power in the area. From this time onwards the Campbells acted as the main instrument of central authority in the area and this could be the real cause of the ancient enmity between the Campbells and the MacDonalds.