Fiacha Sraibhtine, son of Cairbre Lifechair, was, according to medieval Irish legend and historical tradition, a High King of Ireland.
Fíacha and the fianna then defeated and killed Fothad in the Battle of Ollarba.
Fíacha's son, Muiredach Tirech, commanded his armies, as the king himself was not allowed to go into battle.
Fíacha's druid, Dubchomar, prophesied that if Fíacha was to defeat the Collas, none of his descendants would ever rule Ireland, and likewise, if the Collas won, none of their descendants would be king after them.
The chronology of Geoffrey Keating's Foras Feasa ar Éirinn dates his reign to 273–306, the Annals of the Four Masters to 285–322.