Cathair Mór ("the great"), son of Fedlimid Fir Urglais, a descendant of Mug Corb, was, according to medieval Irish legend and historical tradition, a High King of Ireland. He took power after the death of Fedlimid Rechtmar.[1] He is said to have had thirty sons, but only ten of them had children; several medieval dynasties of Leinster traced their ancestors to them.[2][3] His daughter Cochrann was said to have been the mother of the fenian hero Diarmuid Ua Duibhne.[4]
He features in the saga Esnada Tige Buchet ("The Melody of the House of Buchet"). Cathair's daughter Eithne Tháebfhota is fostered by a hospitable Leinsterman named Buchet who has many herds of cattle, but Cathair's sons so exploit Buchet's hospitality that he is left with only one bull and seven cows, and the king, now old and enfeebled, is unable to restrain them. Buchet and his family, including Eithne, are reduced to living in a hut in the forest in Kells, County Meath. Later, when Cormac mac Airt is king, he marries Eithne and restores Buchet's fortunes[5] (in other stories the king who marries Eithne is Cathair's successor Conn Cétchathach).[6] In another saga, Fotha Catha Cnucha ("The Cause of the Battle of Cnucha"), Cathair gives the hill of Almu (Knockaulin, County Kildare) to the druid Nuada son of Aichi. This hill will later be famous as the home of Nuada's great grandson Fionn mac Cumhaill.[7]
Cathair ruled for three years, at the end of which he was killed by the Luaigne of Tara, led by Conn Cétchathach. The Lebor Gabála Érenn synchronises his reign with that of the Roman emperor Marcus Aurelius (161-180). The chronology of Geoffrey Keating's Foras Feasa ar Éirinn dates his reign to 113-116, that of the Annals of the Four Masters to 119-122.[8]
Child(ren):