Conchobar Abradruad son of Find File, son of Ros Ruad, son of Ferhus Fairgge, son of Nuadu Necht, of the Laigin

Leinster

Leinster is one of the Provinces of Ireland situated in the east of Ireland. It comprises the ancient Kingdoms of Mide, Osraige and Leinster. Following the Norman invasion of Ireland, the historic fifths of Leinster and Mide gradually merged, mainly due to the impact of the Pale, which straddled...

, 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 succeeded to the throne after the death of Lugaid Riab nDerg

Lugaid Riab nDerg

Lugaid Riab nDerg or Réoderg , son of the three findemna, triplet sons of Eochu Feidlech, was, according to medieval Irish legend and historical tradition, a High King of Ireland.-Conception:...

, and ruled for a year, at the end of which he was killed by Lugaid's son Crimthann Nia Náir

Crimthann Nia Náir

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

. 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...

 Vespasian

Vespasian

Vespasian , was Roman Emperor from 69 AD to 79 AD. Vespasian was the founder of the Flavian dynasty, which ruled the Empire for a quarter century. Vespasian was descended from a family of equestrians, who rose into the senatorial rank under the Emperors of the Julio-Claudian dynasty...

 (AD 69-79). 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 13-12 BC, that of 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...

to 9-8 BC.