The Three Welsh Romances are three Middle Welsh tales associated with the Mabinogion. They are versions of Arthurian tales that also appear in the work of Chrétien de Troyes. Critics have debated whether the Welsh Romances are based on Chrétien's poems or if they derive from a shared original. The Romances survive in the White Book of Rhydderch and the Red Book of Hergest, both from the 14th century, though the material is at least as old as Chrétien.

The Mabinogion are the earliest Welsh prose stories, and belong to the Matter of Britain. The stories were compiled in Middle Welsh in the 12th–13th centuries from earlier oral traditions. There are two main source manuscripts, created c. 1350–1410, as well as a few earlier fragments. The title covers a collection of eleven prose stories of widely different types, offering drama, philosophy, romance, tragedy, fantasy and humour, and created by various narrators over time. There is a classic hero quest, "Culhwch and Olwen"; a historic legend in "Lludd and Llefelys", complete with glimpses of a far off age; and other tales portray a very different King Arthur from the later popular versions. The highly sophisticated complexity of the Four Branches of the Mabinogi defies categorisation. The stories are so diverse that it has been argued that they are not even a true collection.