The Mabinogion is a collection of Welsh medieval tales, most in prose. The title is a 19th century fabrication by Lady Charlotte Guest who was the first to translate them into English and publish them. The word "mabinogi" probably means a tale of a hero.
The tales are preserved in two manuscripts of the 14th - 15th centuries, the White Book of Rhydderch (Llyfr Gwyn Rhydderch) and the Red Book of Hergest (Llyfr Coch Hergest).
The Four Branches
The first four tales, known as the Four Branches of the Mabinogion, have been interpreted as developments from the story of the birth, life and death of the hero Pryderi, but much changed. Pwyll Prince of Dyfed recounts his birth. He has all but disappeared from the second branch, Branwen daughter of Llŷr. In the third, Manawydan, son of Llŷr, Pryderi is imprisoned in the Otherworld and freed by Manawydan. The fourth, Math son of Mathonwy, contains his death, though it is subordinated to other elements in the story, which has become the story of Llew Llaw Gyffes. Each of the tales ends with a statement that it is a branch of the mabinogi. They are all complex narratives, and on the whole have identifiable locations
It is possible that the principal characters in these tales are humanised Celtic deities.
The story of Llew Law Gyffes was used by Alan Garner as the background for his novel The Owl Service.
Two short tales
The Dream of Macsen Wledig is the tale of a Roman emperor who, as a result of a dream, conquers the island of Britain and then has to re-conquer his original empire. In Lludd and Llefelys, Lludd, by the advice of his brother Llefelys, rids his realm of Britain of three supernatural plagues.
Five Arthurian tales
The first two Arthurian tales are manifestly older than the others, and give some idea of the background out of which the corpus of Arthurian legend emerged. Compared with the stories of Arthur as developed by Anglo-French writers and popularised by Malory and Tennyson, there are very few recognisable names, and the characterisation is completely different. Culhwch and Olwen tells of Culhwch's winning of Olwen, daughter of the giant Ysbaddaden, by performing many remarkable feats with the aid of Arthur and many of his gifted enourage. The Dream of Rhonabwy depicts further Arthurian exploits, in a dream of the past, in which the "small men" of the present are held up to derision.
The remaining three tales, The Lady of the Fountain, Peredur son of Efrawg, and Gereint son of Erbin show a further stage in the development of the legend. Here are tales of knights rather than warriors, in a landscape of vague geography.