Fiacha Finnolach, son of Feradach Finnfechtnach

Feradach Finnfechtnach

Feradach Finnfechtnach , son of Crimthann Nia Náir, was, according to medieval Irish legend and historical tradition, a High King of Ireland...

, was, according to medieval Irish legend and historical tradition, a High King of Ireland

High King of Ireland

The High Kings of Ireland were sometimes historical and sometimes legendary figures who had, or who are claimed to have had, lordship over the whole of Ireland. Medieval and early modern Irish literature portrays an almost unbroken sequence of High Kings, ruling from Tara over a hierarchy of...

. He took power after killing his predecessor, Fíatach Finn

Fiatach Finn

Fiatach Finn mac Dáire, a distant descedant of Óengus Tuirmech Temrach, was, according to medieval Irish legend and historical tradition, a king of the Ulaid, later a High King of Ireland, and the eponymous ancestor of the early Medieval Ulster dynasty of the Dál Fiatach...

. He ruled for fifteen, seventeen, or twenty-seven years, depending on the source consulted, after which he, and the freemen of Ireland, were killed in an uprising of aithech-tuatha or "subject peoples", led, according to the Lebor Gabála Érenn

Lebor Gabála Érenn

Lebor Gabála Érenn is the Middle Irish title of a loose collection of poems and prose narratives recounting the mythical origins and history of the Irish from the creation of the world down to the Middle Ages...

and the Annals of the Four Masters

Annals of the Four Masters

The Annals of the Kingdom of Ireland or the Annals of the Four Masters are a chronicle of medieval Irish history...

, by Elim mac Conrach, or by Cairbre Cinnchait

Cairbre Cinnchait

Cairbre Cinnchait or Caitchenn was, according to medieval Irish legend and historical tradition, a High King of Ireland...

 according to Geoffrey Keating

Geoffrey Keating

Seathrún Céitinn, known in English as Geoffrey Keating, was a 17th century Irish Roman Catholic priest, poet and historian. He was born in County Tipperary c. 1569, and died c. 1644...

. His wife Eithne

Eithne

Eithne is a popular Irish female name meaning 'little fire' and is borne by a variety of historical and legendary figures, including:-Medieval:...

, daughter of the king of Alba

Alba

Alba is the Scottish Gaelic name for Scotland. It is cognate to Alba in Irish and Nalbin in Manx, the two other Goidelic Insular Celtic languages, as well as similar words in the Brythonic Insular Celtic languages of Cornish and Welsh also meaning Scotland.- Etymology :The term first appears in...

 (Scotland), who was pregnant, fled home to Alba, where she gave birth to Fíachu's son, Tuathal Techtmar, who would ultimately return to Ireland to claim the throne. The Lebor Gabála Érenn

Lebor Gabála Érenn

Lebor Gabála Érenn is the Middle Irish title of a loose collection of poems and prose narratives recounting the mythical origins and history of the Irish from the creation of the world down to the Middle Ages...

synchronises his reign with that of the Roman emperor

Roman Emperor

The Roman emperor was the ruler of the Roman State during the imperial period . The Romans had no single term for the office although at any given time, a given title was associated with the emperor...

 Nerva

Nerva

Nerva , was Roman Emperor from 96 to 98. Nerva became Emperor at the age of sixty-five, after a lifetime of imperial service under Nero and the rulers of the Flavian dynasty. Under Nero, he was a member of the imperial entourage and played a vital part in exposing the Pisonian conspiracy of 65...

 (AD 96-98). The chronology of Geoffrey Keating

Geoffrey Keating

Seathrún Céitinn, known in English as Geoffrey Keating, was a 17th century Irish Roman Catholic priest, poet and historian. He was born in County Tipperary c. 1569, and died c. 1644...

's Foras Feasa ar Éirinn dates his reign to AD 28-55, that of the Annals of the Four Masters to AD 39-56.