Y Mabinogion Cymreig: Sef, Chwedlau Rhamantus Yr Hen Gymry. Yn Yr Hen Gymraeg, A'r Gymraeg Bresenol. This book, "Y Mabinogion Cymreig Sef, Chwedlau Rhamantus Yr Hen Gymry", by Mabinogion, is a replication of a book originally published before 1880. It has been restored by human beings, page by page, so that you may enjoy it in a form as close to the original as possible.