The Four Branches of the Mabinogi and other tales collected in the Mabinogion were composed and transmitted in Wales during the 11th and 12th centuries, drawing on ancient Celtic mythology and folklore. These prose narratives with poetic elements preserve Welsh mythological traditions, including tales of Pwyll, Branwen, Manawydan, and Math, alongside Arthurian legends.

The Mabinogion tales preserved Celtic mythological material that influenced later Arthurian romance, particularly through Wace and Chrétien de Troyes who adapted Welsh sources for French audiences. The tales' blend of mythology, magic, and heroic adventure provided source material for medieval and modern literature, while their distinctive narrative structures influenced Celtic Revival writers. The manuscripts demonstrate how Welsh literature maintained indigenous traditions while engaging with continental European literary trends.