The Tain Bo Cuailnge (The Cattle Raid of Cooley) is an epic-like prose work which tells the tale of a war between the province of Connaught, led by Queen Medb and her husband Ailill, and the province of Ulster, represented by the young hero Cuchulainn. The war is the result of Queen Medb’s desire to steal the great stud bull of Ulster, Donn Cuailnge, in order to achieve equality with her husband, who owns another great bull, Finnbhenach. In her war, Medb is assisted by Fergus mac Roich, an Ulsterman who has turned against the Ulster king, Conchobar.

In a series of contacts between gods and humans, we are reminded of the divine interference in Homer’s war epic, the Iliad. When a plague undermines the army of Ulster, it is perhaps caused by the goddess Macha. When the goddess Morrigan, in the form of a beautiful woman, offers to help him, Cuchulainn refuses her, much as Gilgamesh had refused Inanna in the Sumerian epic. Cuchulainn pays for his insult in many ways throughout his life.

The only hope for the ill Ulster forces is the seventeen-year-old Cuchulainn, who fights alone aided by his charioteer Laeg. As hard as he fights, Cuchulainn, who reaches a truce of sorts with Fergus, his foster father, cannot prevent Medb’s capturing of Donn Cuailnge. Once again, divine interference is crucial. The god Lugh, revealing himself as Cuchulainn’s true father, puts his son to sleep for three days so that his wounds can heal. When Cuchulainn awakens, he becomes a wild monster-like warrior who does serious damage to the Connaught army. Finally, in a series of single combats, Cuchulainn is forced to kill his foster brother Ferdiad. In a parallel battle, the bull of Ulster, Donn Cuailnge, fights and kills the bull of Connaught, Finnbhenach. Donn Cuailnge then roams around Ireland before returning home to die.