Manuscripts, [16 cent.]-[?1841], mostly collected or written by Iolo Morganwg. They include transcripts of Welsh poetry, pedigrees, grammars, and manuscripts belonging to Robert Vaughan of Hengwrt, Lewis Morris, Gwallter Mechain, Ieuan Brydydd Hir, Thomas Glyn Cothi, Richard Morris and others; literary papers of Iolo Morganwg, including hymns and psalm-tunes, English and Welsh poetry and Bardic papers; other papers including diaries, memorandum books and notebooks; and accounts of his father, Edward Williams, senior.

Miscellaneous papers created or collected by Iolo Morganwg, including poetry and prose in Welsh and English; autobiographical and biographical material; vocabularies; papers relating to work as a monumental mason, stonemason and builder; broadsides and other political material; Unitarian and theological papers; pedigrees; topographical notes; and advertisements.

Miscellaneous papers of David Evans (Dewi Dawel), including copies of poems by Edward Williams (Iolo Morganwg), Thomas Evans (Tomos Glyn Cothi), J. M. Pughe (Ioan Myllin), and some local bards, many having been written for competitive meetings at Cwmdu, Llandilo, and elsewhere, or to celebrate events in those districts; prose extracts; etc.

Transcripts of letters from John Morgan (Matchin), Lewis Morris, and William Wynn, with notes by Walter Davies; a transcript of Account of MSS. in Wales, written by the learned and ingenious Lewis Morris, as it is supposed about the year 1745 (cf. Panton MS. 29, i.e., N.L.W. MS. 1998); transcripts, by Walter Davies, of Welsh poems allan o Lvyr Med Davis o Vron Wion ym Meirion-a sgrivwyd 1738; etc.

A fragment of a volume described as 'Llyfr Kowyddav y Masdr [Hwmffre] Huws or deirnion siryf veirionydd ...', containing autograph 'cywyddau', some of them eulogising him, by Thomas Penllyn, Rhisiart Phylip, Tuder Owen, Sion Cain, and Huw Machno (some of them being dated 1619), together with other 'cywyddau' by Sion Cent, etc.

Miscellaneous poems, including a 'pryddest' on 'Saccheus ar ben y Sycamorwydden' written for an eisteddfod at Tredegar, 1870; a 'Carol Plygain' and a 'Carol Pasg'; various poems - some of them in the autograph of 'Nefydd' - by 'Giraldus' (Haverfordwest), William Rees ('Gwilym Hiraethog'), Robert Williams ('Robert ap Gwilym Ddu'), 'Gwyliedydd Gwent', William Jones ('Gwilym Ilid'), John Blackwell ('Alun'), etc.; 'Trioedd yr Offeiriad'; and hymns by J. M. Thomas.

'Diferyn Difyrrwch neu ganiadau plygeiniol er coffadwriaeth am ymddangosiad Duw yn y cnawd', being a collection made by G. C. Griffith of 'englynion', 'carolau', and other poems by Robert Hughes (Neuadd y blawd), William Griffith ('Gwilym ab Gryffydd', 1794), John Thomas (Pentrefoelas, 1800), David Owen ('Dewi Wyn o Eifionydd'), G. C. Gryffydd (1816), and Richard Jones (Trefdraeth).

An arithmetical exercise book, with transcripts of 'cerddi' by Thomas Edwards ('Twm o'r Nant') and others, transcripts of 'bidding' letters, and miscellanea.

Miscellanea, 1835-1866 (watermark 1807), including poems by David Davis, Castell Hywel, William Moses, Edward Williams (Iolo Morganwg), William Walters, Daniel Evans (Daniel Ddu o Geredigion), Eliazar Lefi, Rhys Elis (o'r Wayn), William Ellis Jones (Gwilym Cawrdaf), etc., a Welsh version of the words of 'La Marseillaise', 'Llythur at benllywydd y Cy[m]rydorion', 'Trioedd gweddus eu bod ar wraig ...', recipes, notes from sermons, etc.

A composite volume in the hand of the Rev. Evan Evans (Ieuan Fardd) containing Welsh and English poetry (pp. 1-102, 127-207, 215-393, 497-507, 549-664), by Ieuan Fardd himself, Edward Richard, Tudur Aled and Edmwnd Prys and others, as well as extracts from Pope's Messiah (including a Welsh translation) (pp. 33, 47) and a translation from the work of Milton (pp. 215-242). One poem (pp. 153-173) is dedicated to Sir Watkin Williams Wynn. There are also extracts from Virgil's Fourth Eclogue, with Beattie's translation into English (pp. 13-28), from Dryden's translation of Virgil (109: The Song of Simeon) (pp. 103-114), from Lord Lyttelton's history of Henry II (1767) (pp. 115-125), and from 'Llyfr Plas y Ward' ('Ystori Gr: ap Cynan') (pp. 397-428); copies of letters from Dr Tancred Robinson to Robert Davies, Llannerch, and between Robert Davies and William Lloyd, bishop of St Asaph (pp. 429-451); 'A letter on British History' relating to Geoffrey of Monmouth, Humphrey Llwyd and others (pp. 461-492); a copy of a translation, 1629, by the Rev. Richard Lloyd of a work by Arthur Dent (second edition (1683), edited by Charles Edwards, with a copy of Charles Edwards's preface) (pp. 493-496); a copy of the title, dedication, etc. of James Howell's Lexicon Tetraglotton (London, 1660) (pp. 513-548); etc.

'Llyfr Cowyddeu i Mr. William Wynn o Langoed yn sir fon'. 'Y Llyfr hwnn a scrifennodd William Davies Curat or plwy yn y flwyddyn o oedran yr Arglwydd: 1642'. It contains 'cywyddau', 'awdlau', and 'englynion' by Sion Cent, Iolo Goch, Syr Owain ap Gwilym, Syr Dafydd Trefor, Sion Phylip, Dafydd ap Gwilym, Ieuan ap Gruffudd Leiaf, Dafydd Nanmor, Llywelyn ap Hywel ab Ieuan ap Gronw, Edmwnd Prys, Huw Cowrnwy, Dafydd ap Dafydd Llwyd, Maredudd ap Rhys, Gruffudd Llwyd ap Dafydd ab Einion, Sianckyn ab Eingan, Llywelyn ab yr Ynad Coch, Sion Tudur, Morys ap Hywel ap Tudur, Sion ap Hywel ap Llywelyn Fychan, Huw Roberts, Morgan ap Huw Lewis, Sion Brwynog, Morys Llwyd, Hyw Arwystli, Lewis Morganwg, Dafydd Llwyd ap Llywelyn ap Gruffudd, Lewis Daron, Rhys Nanmor, Hywel ap Dafydd ab Ieuan ap Rhys, William Egwad, Hywel Swrdwal, Tudur Aled, Lewis Glyn Cothi, Lewis Môn, Rhys Goch Glyndyfrdwy, Guto'r Glyn, Gruffudd ab Ieuan ap Llywelyli Fychan, Wiliam Myddelton, Bedo Brwynllys, Wiliam Llyn, Lewis Menai, Simwnt Fychan, Llywelyn ap Gwilym ap Rhys, Richard Cynwal, Rhys Cain, Gruffudd ap Tudur ap Hywel, Sion Ceri, Robert ap Dafydd Llwyd, Syr Roland Williams, Gruffudd Hiraethog, Wiliam Cynwal, Morys Dwyfech, Rhys Goch Eryri, Roger Cyffin, Gwilym ap Sefnyn, Ieuan Dew Brydydd, Thomas Prys, Gruffudd Llwyd, Dick Hughes, and the transcriber.

Barddoniaeth o'r ail ganrif ar bymtheg hyd yr ugeinfed ganrif, gan gynnwys gweithiau gan Alan Llwyd (f. 2), W. J. Gruffydd (f. 14), Richard Davies (Mynyddog) (f. 76), Ray Howard-Jones (ff. 98-104), R. Williams Parry (ff. 106-110), Saunders Lewis (ff. 132-136), Vernon Watkins (f. 146), Harri Webb (ff. 153-154), Katherine Philips (The Matchless Orinda) (f. 158), ac Euros Bowen (ff. 161-169), ynghyd â nifer o feirdd llai enwog a rhai darnau anhysbys. Cynigiwyd rai o'r cerddi mewn cystadlaethau eisteddfodol (ff. 36-51, 53-61, 63, 113-124). Mae nifer o'r cerddi yn llaw y beirdd eu hunain, eraill yn gopïau neu mewn teipysgrif. Ceir hefyd garol plygain, a nodwyd i lawr [?19 gan., ¼ olaf] (ff. 155-157 verso), a llythyr, 1994, oddi wrth Jon Meirion Jones at Dafydd Ifans yn Llyfrgell Genedlaethol Cymru yn ymwneud â Dafydd Jones (Isfoel) y Cilie (ff. 149-150). = Poetry, seventeenth to twentieth centuries, including works by Alan Llwyd (f. 2), W. J. Gruffydd (f. 14), Richard Davies (Mynyddog) (f. 76), Ray Howard-Jones (ff. 98-104), R. Williams Parry (ff. 106-110), Saunders Lewis (ff. 132-136), Vernon Watkins (f. 146), Harri Webb (ff. 153-154), Katherine Philips (The Matchless Orinda) (f. 158), and Euros Bowen (ff. 161-169), together with many lesser-known poets and some anonymous pieces. Some of the poems were submitted for competition at eisteddfodau (ff. 36-51, 53-61, 63, 113-124). Many of the poems are autograph while others are copies or in typescript. Also included is a plygain carol, noted down [?19 cent., last ¼] (ff. 155-157 verso), and a letter, 1994, from Jon Meirion Jones to Dafydd Ifans at the National Library of Wales regarding Dafydd Jones (Isfoel), Cilie (ff. 149-150).

A commonplace book belonging to Rowland Eames, Penrhyndeudraeth, 1776-1781, and containing notes on arithmetic, accounts, recipes, 'cerddi' and 'carolau', hymns, precedents of legal documents, music, night-school memoranda, a highway account for Llanfrothen, 1790, etc.

Manuscript collections containing original and transcribed poetry and prose, 1543-[20th century]; religious works, 1611-1914; biographies, chronicles, archaeological and historical notes, works on travel, folklore, recipes, grammars, vocabularies and philological notes, 1673-1900; rent-rolls, parish registers, tithe account books, bidding books, minute books and registers of various societies, 1608-1863; pedigrees and genealogical notes, [17th century]-1871, commonplace books, [18th century]-1904, volumes of press-cuttings; manuscripts in the hand of J. H. Davies, including transcripts of and indexes to Welsh poetry, bibliographical notes, literary and legal extracts, pedigrees, biographical data and notes on place-names, 1891-1923; autograph letters from prominent Welsh literary figures, 1674-1921; autograph manuscripts of John Jones, Gellilyfdy, Dafydd Ellis of Criccieth, Eben Fardd (including diaries, 1836-1859), Peter Williams, D. Silvan Evans, Thomas Richards and Myrddin Fardd.

A composite manuscript from the Gloddaeth Library, consisting of cywyddau and Brut y Tywysogion (pp. 35-178).

A volume containing Welsh poetry, mostly in strict metre (pp. 1-433), together with some prose items, including recipes for making inks and baits for catching trout (pp. xvii-xviii), a short Welsh vocabulary (pp. xix-xxii), descriptions of the coats of arms of Welsh families (pp. 444-454) and the names of the Fifteen Tribes of Gwynedd (pp. 454-456), written in a late-seventeenth century hand.
Many of the sixteenth- and seventeenth-century poems are addressed to members of the families of Owen of Clenennau and Brogyntyn and Wynn of Glyn and Ystumcegid: the manuscript was probably compiled for Elizabeth Wynn of Glyn and Ystumcegid or for her daughter Margaret Wynn shortly after the latter's marriage in 1683 to Sir Robert Owen of Clenennau and Brogyntyn (see pp. 23-25). An index to the poems is supplied by the scribe on pp. 434-443. Poetry in more than one hand has been added between c. 1691 and c. 1713 on pp. vii, 457-476, 484-485, 489-510, including elegies to Sir Robert Owen by Huw Morys (pp. 468-471) and to his sister-in-law Mrs Catherine Pennant by David Davies (p. 473), and a poem in free metre, dated 1713, probably by Dafydd Williams, Rhuthun (p. vii).

'Englynion' and other poems, some of them holograph, composed for the most part at informal meetings of bards in the house of John Jenkins, the writers including David Rowland ('Dewi o Brefi'), 'Cedewain', John Jenkins, Walter Davies, David Davies ('Dewi Fardd o Geri'), William Moses ('Gwilym Tew Glan Taf'), John Howell ('Ioan ab Hywel', alias 'Eos Glandyfroedd'), Robert Davies ('Bardd Nantglyn'), David Richards ('Dewi Silin'), Aneurin Owen, Evan Evans ('Ieuan Glan Geirionydd'), Elizabeth Jenkins ('Eos y Bele'), William Ellis Jones ('Gwilym Cawrdaf'), John Jones ('wyr Dafydd Jones o Drefriw'), Hugh Jones ('Huw Erfyl'), John Hughes (author of Horae Britannicae), William Edwards ('Gwilym Padarn'), Thomas Jones ('Thomas Gwynedd', alias 'Tydain'), Daniel Evans ('Daniel Ddu o Geredigion'), Robert Parry ('Robin Ddu Eryri'), Thomas Ellis ('Eos Tegeingl'), Edward Williams ('Iolo Morganwg'), William Owen ('Gwilym Glan Hafren'), John Blackwell ('Alun'), Peter Jones ('Pedr Fardd'), John Jones ('Collwyn'), and David Harris ('Kerry').