kingdom from which an invasion had been launched during the overlordship of Magnús Óláfsson, King of Norway. The alliance with Óláfr also ensured Fergus the protection of one of Britain's most formidable fleets, and further gave him a valuable ally outwith the orbit of the Scottish Crown. One possible reason for Fergus's apparent lack of further participation in Anglo-Scottish affairs may have been due to events in the Isles. Although the thirteenth- to fourteenth-century Chronicle of Mann portrays Óláfr's reign as one of tranquillity, a more accurate evaluation of his reign may be that he adeptly managed to navigate an uncertain political climate. In regard to Fergus, the acquisition of the Dublin kingship in 1142, by the Islesman Ottar mac meic Ottair, may well have represented a threat to the authority of Óláfr, and the prospects of Fergus's grandson. By the mid-part of the twelfth century, however, the ageing Óláfr's realm may well have begun to buckle under the strain, as perhaps evidenced by the depredations wrought on the Scottish mainland by Óláfr's leading ecclesiast, Wimund, Bishop of the Isles. Confirmation of Óláfr's concern over the royal succession may well be preserved by the chronicle, which states that Guðrøðr journeyed to the court of Ingi Haraldsson, King of Norway in 1152, where Guðrøðr rendered homage to the Norwegian king, and seemingly secured recognition of the royal inheritance of the Isles. The following year marked a watershed in the history for the Kingdom of the Isles with the successive deaths of David and Óláfr. The latter was slain by three Dublin-based sons of his exiled brother, after which these men—the Haraldsonnar—partitioned Mann amongst themselves. Once in control, the chronicle reveals that the Haraldsonnar fortified themselves against forces loyal to the kingdom's legitimate heir by launching a pre-emptive strike against Fergus. Although the invasion of Galloway was repulsed with heavy casualties, once the Haraldsonnar returned to Mann the chronicle records that they slaughtered and expelled all resident Gallovidians that they could find. This ruthless reaction evidently reveals an attempt to uproot local factions adhering to Affraic and her son. Whatever the case, within months of his father's assassination, Guðrøðr executed his vengeance. Enstrengthened with Norwegian military support, Guðrøðr overcame his three kin-slaying cousins, and successfully secured the kingship for himself. Rise of Somairle mac Gilla Brigte Midway through the twelfth-century, Muirchertach Mac Lochlainn, King of Tír nEógain pressed forth his claim to