 Dál Riata was ultimately destroyed when Vikings invaded, and established their own domain, spreading more extensively over the islands north and west of the mainland, including Jura.This became the Kingdom of the Isles, but following the unification of Norway, the islands were under tenuous Norwegian authority, somewhat resisted by local rulers, like Godred Crovan.Following Godred's death, the local population resisted Norway's choice of replacement, causing Magnus, the Norwegian king, to launch a military campaign to assert his authority.