Y Myvyrian Archaiology
The Archeological Study of Welsh Poetry
Edited by Owen Jones, Edward Williams, and Owen Pughe.
Published in three volumes between 1801 and 1807, the Myvyrian Archaeology was one of the earliest printed collections of medieval Welsh literature, culled from many manuscripts, including the so-called "Four Ancient Books of Wales." It was printed entirely in Welsh, without translations, and served as the source text for many translators of Welsh literature until the advent of J. Gwenogvryn Evans' diplomatic editions of the medieval Welsh manuscripts.
Unfortunately, The Myvyrian Archaiology also used the manuscripts in the collection of Iolo Morgannwg (here using his given name of Edward Williams), who was considered an authority on Welsh literature and folklore at the time, but was revealed as a forger in the twentieth century. However, not all that Morgannwg had was of his own hand, and so the Myvyrian Archaiology does have an important place in the history of Welsh literature.
As said, it was published in three volumes. The first volume were bruts--histories of the Britons, particularly one of the Welsh redactions of Geoffrey of Monmouth's History of the Kings of Britain. The second volume contained the Welsh Triads, though unfortunately in Morgannwg's "improved" form (i.e., his rewrites and additions, including adding an entire third of the triads, the so-called "third series")1. The third volume consisted of poetry from various legitimate manuscripts, including The Black Book of Carmarthen, The Red Book of Hergest, The Book of Taliesin, The Book of Aneurin, The Red Book of Talgarth, as well as many unnamed manuscripts. Of course, it also includes some of Morgannwg's forgeries, but that is to be expected.
There would not be an undertaking of this scale for another forty years, until the publishing of Lady Charlotte Guest's Mabinogion, the first fully translated edition of these traditional Welsh romances and mythologies.
The third volume is still in print, though hard to find:
Jones, Owen E. Poetry of the Gogynfeirdd from the Myvyrian Archaeology of Wales. New York: AMS Press, Incorporated.
It is interesting to note that Owen Jones is often called a "peasant" and that part of the legend surrounding the book is that "a poor peasant put up his life savings in order to collect and publish this book." Mr. Jones was in fact a London furrier, and not a peasant but a part of the middle class; moreover, he was working with Dr. Pughe (formerly Owen Williams), who was certainly educated, and Iolo Morgannwg, who made his money by being, well, eccentric and Welsh.
NOTES
1. "These Triads, in so far as they are not fabricates of Iolo Morganwg {sic}, are the works of Welsh antiquarians between the sixteenth and eighteenth centuries." --E. G. Brown. "Tair Gwelygordd Santaidd Ynys Prydain." Studia Celtica. vol. 5. Cardiff: University of Wales Press, 1970. p. 1.