The Mabinogion is a collection of stories based on the oral tradition of the Welsh bards. They are partly based on early medieval historical events, but may hark back to older iron age traditions.
Its name comes from a misunderstanding made by the Mabinogion's first English translator, Lady Charlotte Guest: she found in one story the Welsh word mabynogyon and assumed it was the plural form of the Welsh mabinogi. The word mabinogi itself is something of a puzzle, although it is clearly related to the Welsh mab or "son, boy". Professor Eric P. Hamp suggests that mabinogi derives from the name of the Celtic deity Maponos, and refers to the materials pertaining to the god Maponos.
The Mabinogion appears in two Medieval Welsh manuscripts, the White Book of Rhydderch (Llyfr Gwyn Rhydderch) written AD 1300-1325, and the Red Book of Hergest (Llyfr Coch Hergest) written 1375-1425, although fragments of these tales have been preserved in earlier thirteenth century manuscripts. Scholars agree that the tales are older than the existing manuscripts, but disagree over just how much older. Sir Ifor Williams offered a date prior to 1100, based on linguistic and historical arguments, while later Saunders Lewis set forth a number of arguments for a date between 1170 and 1190; T.M. Charles-Edwards, in a paper delivered to the Honourable Society of Cymmrodorion, discussed the strengths and weaknesses of both viewpoints, and while critical of the arguments of both scholars, notes that the language of the stories best fits the period between 1000 and 1100, although much more work is needed.
The question of the date of the Mabinogion is important because if it can be shown to have been written before Geoffrey of Monmouth's Historia Regum Britaniae, then the value of these stories as evidence for the early folklore and culture of Wales is that much stronger.
The Mabinogi proper consists of four stories, also called "The Four Branches of the Mabinogi." These stories are:
Since the Mabinogion's first compilation and translation by Lady Guest, seven other tales have been associated with the Four Branches. There are four stories that retell material from Welsh tradition and legend:
The tales Culhwch and Olwen and The Dream of Rhonabwy have interested scholars because they preserve older traditions of King Arthur. The tale The Dream of Macsen Wledig is a romanticized story about the Roman Emperor Magnus Maximus.
Three tales are Welsh versions of Arthurian Romances that also appear in the work of Chrétien de Troyes. While nineteenth century critics believed that these works were based on Chretien's own poems, some more recent critics have leaned towards believing that these two collections are based independently on a common ancestor.
Also included by Lady Guest but dropped from later English translations which yet continue to use Guest's term Mabinogion is an eighth tale not found in the Red Book or White Book: