Táin Bó Cúailnge (Irish pronunciation: [t̪ˠaːnʲ boː ˈkuəlʲɲə]; "the driving-off of cows of Cooley", commonly known as The Cattle Raid of Cooley or The Táin) is a legendary tale from early Irish literature, often considered an epic, although it is written primarily in prose rather than verse. It tells of a war against Ulster by the Connacht queen Medb and her husband Ailill, who intend to steal the stud bull Donn Cuailnge, opposed only by the teenage Ulster hero Cú Chulainn.
Traditionally set in the 1st century in an essentially pre-Christian heroic age, the Táin is the central text of a group of tales known as the Ulster Cycle. It survives in three written versions or "recensions" in manuscripts of the 12th and later centuries, the first a compilation largely written in Old Irish, the second a more consistent work in Middle Irish, and the third an Early Modern Irish version.
The Táin is preceded by a number of remscéla, or pre-tales, which provide background on the main characters and explain the presence of certain characters from Ulster in the Connacht camp, the curse that causes the temporary inability of the remaining Ulstermen to fight and the magic origins of the bulls Donn Cuailnge and Finnbhennach. The eight remscéla chosen by Thomas Kinsella for his 1969 translation are sometimes taken to be part of the Táin itself, but come from a variety of manuscripts of different dates. Several other tales exist which are described as remscéla to the Táin, some of which have only a tangential relation to it.