Ollom Fotla son of Fíachu Fínscothach, 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...

. His given name was Eochaid. He took power after killing his predecessor, Faildergdóit, whose father, Muinemón, had killed his father. He is said to have instituted the Feis Temrach or Assembly of Tara

Hill of Tara

The Hill of Tara , located near the River Boyne, is an archaeological complex that runs between Navan and Dunshaughlin in County Meath, Leinster, Ireland...

. 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...

 describes the Feis Temrach as an assembly like a parliament, at which the nobles, scholars and military commanders of Ireland gathered on Samhain

Samhain

Samhain is a Gaelic harvest festival held on October 31–November 1. It was linked to festivals held around the same time in other Celtic cultures, and was popularised as the "Celtic New Year" from the late 19th century, following Sir John Rhys and Sir James Frazer...

 every three years to pass and renew laws and approve annals and records. The Assembly was preceded and followed by three days of feasting. He also built a structure at Tara called the Múr nOlloman or Scholar's Rampart. He ruled for forty years, and died of natural causes at Tara, succeeded by an unbroken sequence of six descendants, beginning with his son Fínnachta

Finnachta

Fínnachta, son of Ollom Fotla, was, according to medieval Irish legend and historical tradition, a High King of Ireland in succession to his father. His given name was Elim. There is said to have been snow of wine in his reign, from which he gained his better-known name...

, followed by two more sons, Slánoll

Slanoll

Slánoll, son of Ollom Fotla, was, according to medieval Irish legend and historical tradition, a High King of Ireland. He succeeded to throne on the death of his brother Fínnachta. It is said that there was no disease during his reign...

 and Géde Ollgothach. 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 those of Arbaces

Arbaces

Arbaces, according to Ctesias, one of the generals of Sardanapalus, king of Assyria and founder of the Median empire about 830 BC. From the inscriptions of Sargon II of Assyria we know one Arbaku of Arnashia as one of forty-five chiefs of Median districts who paid tribute to Sargon in 713 BC...

 and Sosarmus of the Medes

Medes

The MedesThe Medes...

. The chronology of Keating's Foras Feasa ar Éirinn dates his reign to 943-913 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 1318-1278 BC.