 Meanwhile , in a renewal of ancient feuds that same year , Sigtrygg executed Ragnall King of Waterford , in Dublin Ragnall was the grandson of the Ivar , Sigtrygg 's earliest rival , who had contested for Dublin decades before . Echmarcach mac Ragnaill , King of the Isles forced Sigtrygg to abdicate in 1036 . Sigtrygg died in exile , at an unknown place , in 1042 . 
