 The origins of both Godred Crovan and Somerled are obscure— the former may have been an Uí Ímair dynast from Islay, the latter married a Crovan heiress.Thus it is clear that although there were competing factions in play, the Hebrides and islands of the Clyde were essentially under the control of rulers of Scandinavian origin from "at least the late tenth century" until the emergence of the kingdom of Scotland and its 13th century expansion into the west.The early Viking threats may have speeded a long term process of gaelicisation of the Pictish kingdoms, which adopted Gaelic language and customs.