Sétna Airt, son of Artrí, son of Éber, son of Ír, son of Míl Espáine

Míl Espáine

In Irish origin legends, Míl Espáine or Míl Espáne is the ancestor of the final inhabitants of Ireland, the "sons of Míl" or Milesians, who represent the vast majority of the Irish Gaels....

, 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 came to power after the death of the previous incumbent, 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...

, whom, according to one version of the story, he had killed in single combat at Cruachan

Cruachan, Ireland

Rathcroghan is a complex of archaeological sites near Tulsk in County Roscommon, Ireland. It is identified as the site of Cruachan, the traditional capital of the Connachta. While it is debatable whether this was a place of residence, it had huge importance as a cemetery and also hosted some of...

, fighting to protect his son, Fíachu Fínscothach. He ruled for five years, until Fíachu, returning from exile, killed him at Cruachan. 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...

 adds that Fíachu returned to Cruachan in a "black fleet", 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...

says he was assisted in the killing of Sétna by the future High King Muinemón. The chronology of Keating's Foras Feasa ar Éirinn dates his reign to 980-975 BC, that of the Annals of the Four Masters to 1358-1353 BC.