Welsh-language literature has been produced continuously since the emergence of Welsh from Brythonic as a distinct language c. 5th century AD. The earliest Welsh literature (llenyddiaeth Gymraeg) was poetry, which was extremely intricate in form from its earliest known examples, a tradition sustained today. Poetry was followed by the first British prose literature in the 11th century (such as that contained in the Mabinogion). Welsh language literature has repeatedly played a major part in the self-assertion of Wales and the Welsh peoples. It continues to be held in the highest prestige, as evidenced by the massive National Eisteddfod of Wales (Eisteddfod Genedlaethol Cymru), probably the largest amateur arts festival in Europe, which crowns its chosen literary winners in dignified ceremony.
The mediaeval period has three stages. The Earliest Poets wrote praise poems for rulers and lords of Welsh dynasties from Strathclyde to Cornwall. In the 11th century, Norman influence and challenge disrupted Welsh cultures, and the language developed into Middle Welsh. The next period is the Poets of the Princes, when Welsh rulers fought each other and the English in shifting alliances. The first prose literature of Wales was compiled in the 11th century.
The next stage was the Poets of the Nobility. The earliest praise poetry to survive is by the poets Taliesin and Aneirin. Praise poetry was powerful propaganda, inspiring loyalty and courage from the teulu, the warband or retinue of a king, prince or lord. It spread his fame, and that of named warriors, as widely as possible, creating a kind of immortality and glory. The art was so valued that the beirdd (bards) had their liberal rights set out in native Welsh law. The highest levels of the poetic art in Welsh are intensely intricate. The bards were extremely organised and professional, with a structured training which lasted many years. As a class, they proved very adaptable: when the princely dynasties ended in 1282, and Welsh principalities were annexed by England, they found necessary patronage with the next social level, the uchelwyr, the landed gentry. The shift led creatively to innovation – the development of the cywydd metre, with looser forms of structure.