According to the New Columbia Encyclopedia p. 365 (Columbia University Press
1975), Brian Boru (Brian Boroimhe) was a clan prince who developed and expanded
a kingdom in Southern Ireland. Sitric, Norse King of Dublin, formed a coalition
of Norse from Ireland, the Hebrides, the Orkneys, and Iceland, as well as Boru's
Irish enemies. They met in battle on Good Friday, 04 23 1014, at Clontarf, near
Dublin, where the Norse were annihilated. Shortly thereafter, Boru was "murdered
in his tent," but his victory broke the Norse hold on Ireland, after which Ireland
fell into anarchy.