Warrior king in the Ulster cycle of Gaelic literature. In The Cattle Raid of Cooley, Fergus, an exile from Ulster, recalls the deeds of the young Cú Chulainn. Another story tells of the revelation of the Táin in the 7th century by the ghost of Fergus. Fergus is also the subject of poems by William Butler Yeats. He is said to have been shipwrecked off the coast of Northern Ireland AD 320, at the place known as Carrickfergus ("rock of Fergus")
The former king of Ulster during the events of the Ulster Cycle, who was ticked out of kingship by Ness, who made her 7-year-old son Conchobar mac Nessa replace him as king. The foster father of Cormac Cond Longas