Library, Add. MS 31055 (made by Thomas Wiliems in 1596, from a lost intermediary copy made in 1596 by Roger Maurice). References Sources 'White Book of Rhydderch'. In Meic Stephens (Ed.) (1998), The new companion to the literature of Wales. Cardiff : University of Wales Press. . Parry, Thomas (1955), A history of Welsh literature. Translated by H. Idris Bell. Oxford : Clarendon Press. 14th-century books Welsh manuscripts Mabinogion Medieval Welsh literature Welsh-language literature Welsh mythology Peniarth collection