After Ímar 's death , Diarmait appear to have appointed his own son , Murchad ( died 1070 ) , control of Dublin later that decade , as the Annals of the Four Masters accord him the title tigherna Gall , meaning " lord of the foreigners " in 1059 . In 1061 , Murchad invaded Mann and seem to have overthrown Echmarcach . Both father and son was dead by 1072 , and the Annals of Tigernach describe Diarmait on his death that year as King of the Isles ( rí Innsi Gall , literally " king of the isles of the foreigners " ) , a declaration which seem to indicate that , by the eleventh century at least , the kingship of the Isles was contingent upon control of Mann .