Uí Fiachrach

The Uí Fiachrach (Irish pronunciation: [iː ˈfʲiəxrəx]) were a dynasty who originated in, and whose descendants later ruled, the coicead or fifth of Connacht (a western province of Ireland) at different times from the mid-first millennium onwards. They claimed descent from Fiachrae, an older half-brother of Niall Noigiallach or Niall of the Nine Hostages. Fiachrae and his two full brothers, Brion and Ailill, were the collective ancestors of the Connachta dynasty that eventually became the new name of the province. Their mother was Mongfind.

The other two dynasties within the Connachta were the Uí Briúin – descendants of Brion – and the Uí nAilello – descendants of Ailill. The latter sank into obscurity at an early stage but both the Uí Fiachrach and Ui Briuin and their many sub-septs featured prominently in the history of Connacht for one thousand years. In the 12th century, an Ui Briuin descendant, Ruaidri mac Tairrdelbach Ua Conchobair, became High King of Ireland.

The Uí Fiachrach separated into two distinct branches, situated widely apart from each other. The Ui Fiachrach Aidhne settled in the kingdom of Aidhne and established themselves as its new ruling dynasty. The Uí Fiachrach Muaidhe were based along the River Moy in what is now part of County Mayo and County Sligo. It appears that they once constituted a single overkingdom, and ruled or took tribute from the older tribes and nations situated between Aidhne and Muaide, but lost their grip on power by the early 8th century leaving them confined to their own strict territory.

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