The Mabinogion is a collection of ancient tales compiled by medieval Welsh authors between the twelfth and fourteenth centuries. These legends are written in Middle Welsh and are preserved in two medieval manuscripts, the Llyfr Gwyn Rhydderch (the White Book of Rhydderch) and the Llyfr Goch Hergest (the Red Book of Hergest), each appropriately named for the color of its cover. The stories contained in The Mabinogion stem from the much more ancient oral tradition of the Celtic people, who relied on their priestly caste of Druids for their cultural memory. Since the Celts essentially did not have a written language, the Druids served as healers, scholars, and most notably for the purpose of this thesis, as bards. The importance of the storyteller was immeasurably important in ancient culture, and the legends which comprise The Mabinogion have contributed markedly to the ancient folkloric themes of the Celts as well as some of the earliest mythological lore of Great Britain. This thesis seeks to explore The Mabinogion, more specifically the Four Branches of the Mabinogi, and how these legends reflect the Celtic themes of honor, magic and the supernatural, and morality as evidenced by the medieval scribe's preservation of oral tradition and lore.