Celtic mythology harbors the rich narrative tradition of the ancient peoples of Ireland, Scotland, Wales, Brittany, and Gaul. The Druids’ nature worship, the fairy folk (Tuatha De Danann), the otherworld (Tir na nOg), and seasonal cycle festivals are fundamental elements of this tradition.

King Arthur and the Knights of the Round Table, the quest for the Holy Grail, the wizard Merlin, fairy queen Morgan le Fay, the epic of hero Cu Chulainn, and the tales of the Mabinogion are the indelible marks Celtic mythology has left on world literature. This tradition later blended with Christianity to form the foundation of medieval chivalric romances.