A manuscript containing Welsh poetry, including the work of Edmwnd Prys, Sion Brwynog, Guto'r Glyn, Sion Phylip, Sion Tudur, Taliesin, Iolo Goch and others. Pp. 7-58, 61-66, 171-210 are in the hand of Roger Williams, assistant to Bishop William Morgan (1545-1604); pp. 131-137 are in the hand of Dr John David Rhys; and pp. 67-112, 139-152 are in the hand of John Powel of Talgarth, Breconshire (see pp. 67, 139; see also Peniarth MSS 27 and 45). P. 58 contains a note, 1611, in the hand of Roger Williams concerning 'the fees that goeth vpon any person in suinge owt his lyveryes', and on p. 61 is a note, 1617, in the same hand concerning the 'benefactors of the Cathedrall church of Landaphe'. Also included in the manuscript is a sermon 'in praise of theves' (p. 197), triads (pp. 200-201) and medical and veterinary recipes (pp. 199, 210b).

A manuscript containing the 'grammar' of Dafydd Ddu o Hiraddug (fl. before 1400), i.e. his 'llyfr cerddwriaeth' dealing with the structure and art of bardism and verse.
A note on p. 31 records that this manuscript was copied from a book belonging to Wiliam Llŷn (1534 or 5-1580), which had in turn been copied from a book belonging to Dafydd ab Edmwnd (fl. 1450-1490). Cf Mostyn MS 110, Jesus College MS 9, Peniarth MS 62, etc.

A manuscript in the autograph of Moses Williams entitled 'Proper Names of Men & Women in alphabetical order transcribed out of a MS. at Hengwrt'. The list begins with 'Arawn ab Cynfarch, Brenin yr Alban' and ends with 'Ywerydd M. Cyndelig bannawg g. Earddur ab Mor ab Tegerin'.

A manuscript containing lives of saints, etc. An index is included on p. i.
Pages i, 427-433 are in the hand of Moses Williams. A note - 'Pretium £1.4.6 An. 1715' - on the fly-leaf is in the same hand as most of the manuscript. At the end of the Life of St Margaret, which begins at p. 427, the scribe has written 'Felly y terfyna buchedd saint y Marged a esgrifenodd Tho: Evans 1628 fis Mawrth 5 dydd'.

A manuscript in the hand of Moses Williams containing a collection of legal triads.

A manuscript in the hand of Moses Williams containing an index to subjects and phrases in the Welsh laws.

A manuscript in the hand of Moses Williams containing the Interpretation of Dreams from Llanstephan MS 28; and 'Gr. ap kynan twssog kymry a wnaith gyfreth ar y gwyr wrth gerdd' in a seventeenth century hand.

A manuscript containing the laws of Hywel Dda in Welsh. A note in the hand of Moses Williams reads as follows: 'The original MS. (Bibl: Cott: Titus D. IX) whence this was copy'd from was lost in the fire A.D. 1731. So this is the only perfect Copy of this class'.

A manuscript containing transcripts by David Parry from the Red Book of Hergest, together with other poetry, the volume being compiled before it was given to Jesus College, Oxford in 1701. The contents of the volume are as follows: A Welsh Grammar copied from the Red Book of Hergest (col. 1117), with collations by Samuel Williams from Llanstephan MS 3, p. 472 (original foliation I-Vb, 1-7); a copy of the poetry on cols 1143-1356 of the Red Book of Hergest (original foliation 7-12b, original pagination 13-168, 169-265); followed by sixteen leaves at the end of the manuscript containing poems by Robin Ddu o Fôn, Tudur Aled, Rhys Nanmor and others, together with the pedigree of Sir Rhys ap Thomas.
Samuel Williams has copied a good many of the older material in a modernised orthography on the side left blank by the original copyist. There are also marginalia in the hand of Moses Williams. A note, probably in the hand of Samuel Williams, on p. 265 (original pagination) reads 'All the Poetry collated March 27 . 1722'.

A manuscript in the hand of Moses Williams containing 'Kelvyddyd kerdd Davod' (ff. 1-5a), being a copy of pp. 10-16 of Llanstephan MS 28, with a note stating that 'This imperfect Tract I transcribed out of a MS. writ by Guttyn Owain A.D. 1455 & communicated to me by D Foulkes of Llanbedr Dyffryn Clwyd.'; and an extract 'Out of Huw Machno's Book' (ff. 5b-12b) outlining the fifteen faults which may be committed when writing Welsh verse, with examples. The text cites a line from Wiliam Cynwal.

A manuscript containing a copy of Aristotle's Book of Physiognomy (originally written by Aristotle for Alexander the Great) (ff. 1-9) (cf. Jesus College MS 7, p. 48); material relating to astrology (ff. 10-26); and Traethiad Robin Moyses (ff. 26-28).
The two works contained in ff. 1-19 are copied from a manuscript written by John Jones, Gellilyfdy in 1604, which was copied by Jones from a manuscript written in 1476.

A manuscript, in the hand of Evan Evans (Ieuan Fardd), containing 'Cerddwriaeth Simwnt Fychan' (ff. 1-43 verso, first sequence) and the 'Rhetoreg' of William Salesbury, which was originally a translation of a Latin treatise on rhetoric (ff. 1-47, second sequence).
There are copious references to the source materials for both parts, the names mentioned including John Jones, Gellilyfdy, William Maurice and Roger Morris (ff. 1 (first sequence), 46 verso (second sequence)). A note by Ieuan Fardd states that he transcribed these works in 1776 (f. 46 verso). For Simwnt Fychan's 'Cerddwriaeth' see also Peniarth MS 159 and Jesus College MS 9.

A composite volume, mainly in the autograph of Evan Evans (Ieuan Fardd), copied from manuscripts of Lewis Morris and others 'ynghylch y flwyddyn 1765' (p. i), including 'Englynion y Beddau' (pp. 1-15) and 'Englynion y Clywed' (pp. 15-28); 'Gildas Nennius' (pp. 49-60). The second part (ff. 1-35) contains 'Hanes Taliessin' (pp. 61-69); genealogies taken from a manuscript of Robert Vaughan, Hengwrt (pp. 80-89); extracts from Dares Phrygius, Brut y Brenhinedd and Brut y Tywysogion (pp. 97-101); Bonedd y Saint (pp. 109-115); 'Hanes yr ymrysson rhwng Edmund Prys a W. Cynwal' (pp. 117-123); notes and extracts; etc.
A letter, 7 December 1758, from Lewis Morris, Penbryn, to Evan Evans, Llanllechid, is tipped into the volume (pp. 135-138).

A manuscript, 'ex Autographo D'ni H. Salesbury de Llan rwst penes dnm R. Salesbury de Rug', containing pedigrees and poetry.
Pp. 1-22 are in the hand of David Parry, and pp. 23-36 probably also in his hand. The poets cited include Taliesin, Sion Tudur and Dafydd ab Edmwnd.

A manuscript containing theological tracts (pp. 408-435), Yspryt Guido Ar Prior (pp. 436-471), Kerdwriaeth Kerd Davawd and Trioed Kerd (pp. 472-504).
The first folio is rubbed, stained and mostly illegible. The text of pp. 408-421, l.8 is practically identical with that published in Llyvyr Agkyr Llanwivrevi (Oxford, 1894), pp. 141-51, l. 3, but wanting the text on p. 144, l. 21 to p. 148, l. 26. The ending of Trioed Kerd is illegible. This manuscript is a continuation of 'Didrefn Gasgliad' Vols I & II.

A manuscript containing Brut y Tywysogion interspersed with the remarks and comments of Dr Powel's edition of H. Lloyd [Humphrey Llwyd]: Historie of Cambria now called Wales (1584) (although certain references in the margins to the pages of Dr Powel's edition do not tally with the 1584 edition). The compiler has also added comments of their own in English, and continued the history down to 1544.

A manuscript containing a chronology, mainly of kings and rulers of Wales (pp. 1, 33-37, 43-48, 49-60, 100, 111-113); arms, mainly of kings and rulers of Wales (pp. 2-8, 9, 99); pedigrees, mainly of kings and rulers of Wales and England (pp. 9b-88, 89-98, 224-152, 155-158, 164-186, 188); and poetry, which includes triads (pp. 38-42, 100-110, 159-163, 187, 190).
The folios of different manuscripts, or of one manuscript written by different hands at different times, have been mixed together in binding.

A manuscript containing the works of the medieval Welsh bards, being a transcript by William Maurice, Llansilin (see p. 492) of British Museum Addl MS 14869. Pp. 69, 119 and 141 bear respectively the dates 1September, 4 October and 6 October [16]66; however, according to an autograph statement by William Maurice at the end of Addl MS 14869 (p. 245b), he completed the transcript on 24 November 1662.
Maurice notes (pp. 473-474) that the original manuscript (now known as British Museum Addl MS 14869), from which this text was transcribed, was partly written temp. Edward II and Edward III and partly temp. Henry V. In an autograph statement on pp. 473-474 William Maurice notes that this original manuscript was once in the possession of Gruffydd Dwnn (c. 1500-c. 1570), Huw Llŷn (fl. 1532-1594) and Rhys Cain (d. 1614), and subsequently came into the possession of Robert Vaughan 'or Wengraig ger llaw Dolgellau' (i.e. Robert Vaughan, Hengwrt (1592-1667)). A later note by 'M. W[illiams]' (p. 474) dated 1728 states that this original manuscript was then at Hengwrt.

A transcript of the Book of Aneurin by M. Williams. It is an excellent copy: an effort has been made throughout to exhibit the difficulties and peculiarities of the original, and any errors, which are due chiefly to an inability to distinguish between 'r' and 't', are infrequent. The transcript is signed 'M. Williams, M.A., F.R.S., Dolgelleu, Oct. 15. 1728' and the flyleaf is inscribed 'O hen Lyfr ar Femrwn yn Hengwrt A.D. 1728', which suggests that the original manuscript, from which the text was transcribed, was at the time at Hengwrt.