Brian Boru (Middle Irish: Brian Bóruma mac Cennétig; modern Irish: Brian Bóramha; c. 941 – 23 April 1014) was the High King of Ireland from 1002 - 1014. He ended the domination of the High Kingship of Ireland by the Uí Néill, and is likely responsible for ending Viking invasions of Ireland. Brian Boru is mentioned in the Annals of Inisfallen and in Chronicon Scotorum as "Brian mac Cennétig" (Brian, son of Cennétig).
https://en.wikipedia.org/wiki/Brian_Boru