The main source for Irish mythology and heroic traditions are four major groups of stories, or cycles: - the Mythological Cycle, which deals with deities and the origins of the Irish;
- the Fenian Cycle, which deals with the hero Finn mac Cumaill and his band of warriors, the Fian;
- the Historical Cycle, or Cycles of the Kings, which includes tales of early medieval Irish kings;
- the Ulster Cycle, which centres around the kingdom of Ulster, its king, and its foremost hero, Cú Chulainn.