The Tuatha De Danann
What books contain the hero stories?
The heroic narratives are contained in several works written by Christian monks in the eleventh and twelfth centuries, based on material from as early as the eighth century C.E. The Lebor na hUidre (Book of the Dun Cow) contains part of the Tain Bo Cuailnge (The Cattle Raid of Cooley), the most famous of the narratives which make up what is called the Ulster Cycle, or the Red Branch Cycle. Other important works are the Lebor Laignech (The Book of Leinster), the so-called Rawlinson manuscript, and several fourth- and fifth-century books, including most importantly the Leabhar Buide Leacain (The Yellow Book of Lecan), which contains most of the Ulster Cycle.
A second great heroic cycle is the Fenian, or Ossianic, Cycle, which contains heroic tales from various works, some as early as the eighth century.
Other heroic cycles are the Mythological Cycle containing the stories of the Tuatha de Danann discussed above, and the Historical Cycle, which is made up of the stories of the early Irish kings.