Irish Mythology is expressed in four main cycles that make up the bulk of Irish oral tradition: the Mythological Cycle, the Ulster Cycle, the Fianna Cycle, and the Cycle of the Kings (Rees, 26).  Each of these cycles is further broken down into collections of shorter stories with a shared focus or theme.  The Ulster Cycle, for example, centres on a continual war waged between Ulster and Connacht, and the plight of the men of Ulster.  In one of the central tales of the Ulster Cycle, the Táin Bó Cuailnge (The Cattle Raid of Cooley), Connacht invades Ulster to steal the Donn Cuailgne (the Brown Bull of Cooley), and the Ulstermen leave the young hero Cuchúlainn alone to face the invading Connacht troops (Táin Bó Cuailnge). Much of early Irish literature has been lost through the ages, but some medieval manuscripts still survive. The Táin Bó Cuailnge for example survives in its earliest form in Lebor na hUidre, familarly known as the Book of the Dun Cow. The manuscript was composed at Clonmacnoise in the twelfth century.
            The Táin Bó Cuailnge represents the oldest vernacular tale of Western Europe, predating both Beowulf and Homer’s Odyssey (Butler).   It was In addition to its historical interests, it has been profoundly significant within the Irish literary tradition, influencing such giants as WB Yeats, Lady Augusta Gregory, JM Synge, Frank McCourt, and Seamus Heaney (Fadave).