Foras Feasa ar Éirinn [SEP] language of work or name
Foras Feasa ar Éirinn
Foras Feasa ar Éirinn – literally, "Foundation of Knowledge on Ireland" but most often known in English as "The History of Ireland" – is a narrative history of Ireland by Geoffrey Keating, written in Irish and completed . 
Outline.
It begins with a preface in which Keating defends the honour of Ireland against the denigrations of writers such as Giraldus Cambrensis, followed by a narrative history in two parts: part one, from the creation of the world to the arrival of Christianity in
Foras Feasa ar Éirinn" dates his reign to 113–116, that of the "Annals of the Four Masters" to 119–122.
Genealogy.
According to Foras Feasa ar Éirinn, Cathaoir Mor was a son of Feidhlimidh Fiorurghlas, son of Cormac Gealta Gaoth, son of Nia Corb, son of Cu Corb, son of Mogh Corb, son of Conchubhar Abhradhruadh, son of Fionn File, son of Rossa Ruadh, son of Fearghus Fairrge, son of Nuadha Neacht, son of Seadna Siothbhac,son of Lughaidh Loithfhionn,