The power of the Vikings was broken in 1014 at the battle of Clontarf, in which armies of the provinces of Connacht and Munster, under Brian Boru, defeated those of Leinster, under King Maelmordha, for the high-kingship of Ireland. Viking contingents fought on both sides, but the destruction of Maelmordha’s forces also entailed breaking the grip of the Norse King Sitric on Dublin, which because of its fleets and anchorage facilities had effectively grown into the commercial and political capital of the country.
