Photostat facsimiles and photographs of the Merthyr Mawr fragment of The Canterbury Tales of Geoffrey Chaucer, being three imperfect folios from an early fifteenth century text of the Nonnes Preestes Tale. The three folios originally contained II. [15]-94, [253]-332, and [417]-96 of the text. Among later marginal additions are couplets in strict metres by Tudur Aled.

A miscellany of texts in prose and verse, mainly in English but a few in Latin. The volume was written by sixteen scribes (see Daniel Huws (1996), pp. 190-199, now superseding Auvo Kurvinen (1953)), with writing styles varying from bastard secretary (ff. 8 verso-11) to fere-textura; ink varying from light to very dark brown and dark sepia. A selection of ten texts from the manuscript was published in Early English Miscellanies in Prose and Verse, ed. by J. O. Halliwell (London, 1855).
Among the main texts are the Arthurian romance 'Sir Gawaine and the Carle of Carlyle' (ff. 12-26), a treatise on the limning of books (ff. 33-52 verso), a life of St Catherine of Alexandria (ff. 91-129) and a prose version of the Middle English poem 'The Siege of Jerusalem' (ff. 157 verso-184). Ancilliary materials, [mid-20 cent.], comprising typescript notes relating to the manuscript are filed separately (Brogyntyn MS II.1a).