eleventh centuries. This could mean that Echmarcach's expulsion of Sitriuc was a direct act of vengeance for the latter's slaying of Ragnall ua Ímair (then King of Waterford) the year before. Little is known of Echmarcach's short reign in Dublin other than an attack on Skryne and Duleek, recorded by the seventeenth-century Annals of the Four Masters in 1037. This strike could have been undertaken in the context of the Dubliner's gradual loss of power in Brega, and an attempt to regain authority of Skryne. Although there is no direct evidence that Echmarcach controlled Mann at this point in his career, Sitriuc does not appear to have taken refuge on the island after his expulsion from Dublin. This seems to suggest that the island was outwith Sitriuc's possession, and may indicate that Mann had fallen into the hands of Echmarcach sometime before. In fact, it is possible that Echmarcach may have used the island to launch his takeover of Dublin. Strife in the Isles, Ireland, and Wales The evidence of Þórfinnr's power in the Isles could suggest that he possessed an active interest in the ongoing struggle over the Dublin kingship. Þórfinnr's predatory operations in the Irish Sea region may have contributed to Echmarcach's loss of Dublin in 1038. Just as Echmarcach may have seized upon Knútr's demise to expand, it is possible that the vacuum caused by Knútr's death allowed Þórfinnr to prey upon the Irish Sea region. Certainly, the corresponding annal-entry of the Annals of Tigernach—stating that Ímar mac Arailt succeeded Echmarcach as King of Dublin that year—appears to indicate that Echmarcach had been forced from the kingship. Ímar appears have been a descendant (possibly a grandson) of Amlaíb Cuarán, and thus a close relative of the latter's son, Sitriuc, whom Echmarcach drove from the kingship only two years before. It is possible that Ímar received some form of support from Knútr's son and successor in England, Haraldr Knútsson, King of England. The latter was certainly in power when Ímar replaced Echmarcach, and an association between Ímar and Haraldr Knútsson could explain why the Annals of Ulster reports the latter's death two years later. The fact that Ímar proceeded to campaign in the North Channel could indicate that Echmarcach had held power in this region before his acquisition of Mann and Dublin. Whatever the case, Ímar's reign lasted only eight years. In 1046, the Annals of the Four