Ailill son of 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...

, 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 cousin Berngal. He ruled for twelve, fifteen or sixteen years, according to various versions of 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...

(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...

 and 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...

 agree on sixteen) before he was killed by Sírna Sáeglach, a great grandson of Rothechtaid mac Main

Rothechtaid mac Main

Rothechtaid, son of Maen, son of Óengus Olmucaid, was, according to according to medieval Irish legend and historical tradition, a High King of Ireland. He came to power by killing the previous incumbent, his grandfather's killer Énna Airgdech, in the battle of Raigne. He ruled for twenty-two...

. The Lebor Gabála synchronises his reign with that of Deioces

Deioces

Deioces, Diyako or Deiokes was the first king of the Medes according to Herodotus. In the late 8th century BC there was a Daiukku or Dayukku who was a Mannaean provincial governor...

 of the Medes

Medes

The MedesThe Medes...

 (694-665 BC). The chronology of Keating's Foras Feasa ar Éirinn dates his reign to 831-815 BC, that of the Annals of the Four Masters to 1197-1181 BC.