This Welsh-language chronicle was published in 1860 for the Rolls Series. With facing-page translation into English, it was edited by John Williams, also known as Ab Ithel (1811-62), using the Red Book of Hergest as the base text and four other extant manuscripts, all of which are translations into Welsh of the missing Latin source. Williams extensively edited works of Welsh history and language, though his accuracy has been criticised. This text, possibly written by Caradoc of Llancarfan up to c.1150, then completed by monks or bards of the Strata Florida monastery, covers Welsh history from the seventh century to the thirteenth, with entries on natural disasters, changes in the church calendar and the deaths of royalty, including also romances, popular tales and poems. It is of interest to scholars studying the historiography of Wales and developments in the textual criticism of its important manuscripts.