A volume, early 18 cent., containing an imperfect copy of a modernised version of the Historia of Geoffrey of Monmouth, which appears to correspond to the version in Brit. Mus. Addit. MS 14872, pp. 33-257. The Brit. Mus. manuscript is supposed to have been written by Thomas Prys of Plas Iolyn and NLW MS 11D is stated to have been copied in 1694 from a book written by Thomas Prys, but the two versions are quite different. NLW MSS 11D and 312D were both at one time in the possession of the same person; also pp. 263-4 of NLW MS 11D are really part of NLW MS 312D and have now been placed with it. Brit. Mus. Addit. MS 14872 is imperfect and begins on p. 2, l. 30 of NLW MS 312D, both manuscripts ending with the year 8 Charles II. All the poetry in NLW MS 312D is in the hand of Richard David of Llanymawddwy, who owned both NLW MS 312D and NLW MS 11D during the first quarter of the 18th century. NLW MS 312D also contains warrants, dated 1705, 1711, 1713-1714, relating to land tax in the hundred of Mawddwy.