“Book Descriptions: Y Gododdin is a medieval Welsh poem consisting of a series of elegies to the men of the Brittonic kingdom of Gododdin and its allies who, according to the conventional interpretation, died fighting the Angles of Deira and Bernicia at a place named Catraeth in about AD 600. It is traditionally ascribed to the bard Aneirin and survives only in one manuscript, the Book of Aneirin.
The Book of Aneirin manuscript is from the later 13th century, but Y Gododdin has been dated to between the 7th and the early 11th centuries. The text is partly written in Middle Welsh orthography and partly in Old Welsh. The early date would place its oral composition soon after the battle, presumably in the Hen Ogledd ("Old North"); as such it would have originated in the Cumbric dialect of Common Brittonic. Others consider it the work of a poet from Wales in the 9th, 10th, or 11th century. Even a 9th-century date would make it one of the oldest surviving Welsh works of poetry.” DRIVE