Celtic literature refers to the body of written works produced by the Celtic peoples, primarily in the languages of Irish, Scottish Gaelic, and Welsh. This literature encompasses a wide range of genres, including mythology, poetry, folklore, and historical narratives. Notable works include the Táin Bó Cúailnge from Irish mythology and the Mabinogion from Welsh folklore. The origins of Celtic literature can be traced back to ancient oral traditions, which were later transcribed by monks during the medieval period. Themes often revolve around heroism, nature, and the supernatural, reflecting the rich cultural heritage of the Celtic nations.