Manuscripts, [late 12 cent.]-[early 20 cent.], formerly part of the library of the Mostyn family of Mostyn Hall, Flintshire, comprising transcripts and extracts from Giraldus Cambrensis, Geoffrey of Monmouth, Dares Phrygius, Nennius, Gildas, David Jenkins (Judge Jenkins), Sir John Wynn of Gwydir, Lydgate's 'Life of Our Lady', Leland's Itinerary, 'Chroniques de France', historical manuscripts such as Brut y Tywysiogion and Brut y Brenhinoedd, Welsh romances and the Mabinogion; collections of mainly Welsh poetry, among them the seventeenth-century volumes Llyfr Coch Nannau and Llyfr Gwyn Corsygedol, containing poems by Dafydd ap Gwilym, Guto'r Glyn, Tudur Aled, Siôn Cent and others; genealogies, pedigrees and histories; official papers relating to Caernarvonshire; catalogues of the Mostyn and Gloddaeth libraries, 1692-1842; etc.

Llangibby Castle estate records, including court rolls of manors in Monmouthshire, 1262-1911, Glamorgan, 1675-1739, Gloucestershire, 1427-1595, and Somerset, 1609-1691; title deeds, mainly Monmouthshire, 1217-1930, and correspondence, mainly 18-19 cent.; important letters and papers relating to the civil war in Monmouthshire; and manuscripts aquired by the family, including drafts and copies of Modus Tenendi Parliamentarum and Observata Parliamentaria by Henry Elsynge, junior (1598-1654), clerk to the House of Commons, together with minutes of the House of Commons, 1624-1626, calendar of the Journal of the House of Lords, 1647-1768, copies of the Journals of the House of Commons, 1547-1701, index to parliamentary proceedings, temp. Edward III-Edward IV, and, 1724-1743, civil war tracts, the journal of the missionary Dr Joseph Wolff, 1832, 'Prif Achae holh Gymru Benbaladr' in the autograph of Sir Thomas Wiliams, Trefriw, 1578-1609, a seventeenth-century collection of Welsh poetry by the principal 'cywyddwyr'; a memoir of Richard Robert Jones ('Dic Aberdaron', 1780-1843) in his own autograph; English sermons and miscellaneous notes by Rev. Edmund Jones, Pontypool, a sermon notebook of Rev. Philip Henry (1631-1696), the eminent Nonconformist divine, a survey of the lands of Henry, earl of Pembroke, in Glamorgan and Monmouthshire, 1570, and a survey of lands in the lordship of Usk, 1619; pedigree rolls of Sir Roger Williams of Penrhos, Monmouthshire, compiled by Thomas Jones ('Twm Siôn Catti'), 1591, and of the Williams family of Llangibby Castle, probably compiled by Sylvanus Morgan.

A volume containing forty-three odes composed and written by Wiliam Kynwal between 1567 and 1576 (ff. vii verso, 1-93). He began the manuscript at Cerrig Ellgwm 'yn fy siambr vy hun yngheric Ellgwm y trydydd dydd o vis mai o vewn yssbyty dol gynwal a duw a wyr na wnn pwy na[c] ym ha le y gorffennir ef' (ff. v verso-vi). The odes are headed by the arms of the persons addressed, except in the case of the odlau merched, in which quaint sketches of women are substituted.
Also included are a prologue (ff. 5-6) and an incomplete table of contents (f. 6 recto-verso). At the end of the manuscript there is a rough copy of an ode by Huw Machno (ff. 95-96), who has also written some notes on the folios at the beginning (ff. i-iv).

A collection of Welsh strict-metre poetry of the fourteenth, fifteenth and sixteenth centuries, including works by Ieuan Gethin ab Ieuan ap Lleision, Iolo Goch, Lewys Mon, Tudur Aled, Hywel Cilan, Gutun Owain, Guto'r Glyn, Ieuan ap Tudur Penllyn, Dafydd Llwyd o Fathafarn, Rhys Pennardd, Tudur Penllyn, Morus ap Hywel ap Tudur, Deio ab Ieuan Ddu, Gruffudd Hiraethog, Rhys o'r Hengaer, Wiliam Cynwal, Edward Brwynllys, Dafydd Nanmor, Sion Ceri, Huw Arwystl, Dafydd ap Siancyn ap Dafydd ap y Crach, Wiliam Llŷn, Rhys Cain, Rhisiart ap Hywel ap Dafydd ab Einion, Hywel Rheinallt, Gruffudd Llwyd ap Dafydd ab Einion Llygliw, Sion Tudur and Tomas Derllys. A cursory examination of the items included in the manuscript suggests that about ten of the poems are not recorded in other manuscripts. The volume is written in several hands of the late sixteenth century including those of Simwnt Fychan (ff. 73-75) and Wiliam Cynwal (ff. 79-81), two of the bardic pupils of Gruffudd Hiraethog, and also the hand of Rhys Cain, the herald bard of Oswestry, who was a pupil of Wiliam Llŷn, another of Gruffudd Hiraethog's pupils (ff. 4-6 verso, 101 verso-148 verso).

A volume of genealogies of Anglesey families, mostly of the maternal descent. Also included are a cywydd by Ie[u]an Tew Brydydd, 'Kowydd i ofyn cyngor i'r llwynog' by Hugh Lloid (Cynfel) (pp. 156-157) and a poem in free metre, written in 1636.
Five fragments of parchment have been pasted in on pp. 171, 173, 175, 177 and 179.

A volume of Welsh poetry mostly in the hand of Humphrey Davies (Wmffre Dafis), [vicar of Darowen], contining copies of cywyddau and awdlau by well-known and less known poets from the early fourteenth century to the early seventeenth century (pp. 25-492). Some poets are well represented, especially Ieuan Tew, Sion Keri and Huw Arwystl.
Twelve folios at the beginning (pp. 1-24), as well as six (formerly loose) folios at the end (pp. 493-504) are in the hand of Evan Lloyd of Blayn glyn, a former owner of the volume. These include a copy of a version of the dialogue between Hadrian and Epictetus, beginning: 'llyma ymddiddanion Rhwng adram [sic] emerodr Rhufein ag Epig y ddav wr calla yn y bvd', which differs greatly from the text found in Llyfr Yr Angkr and the Hengwrt MSS (pp. 3-7). Two other leaves (now bound in at the end of the volume), one bearing a Welsh poem in free metre (pp. 505-506) and the other an assessment of Derwen parish, [Denbighshire] (pp. 507-508), do not seem to belong to this volume.

A manuscript containing poetry by Iolo Goch, Dafydd ab Edmwnd, Guto'r Glyn, Lewis Glyn Cothi, Wiliam Llŷn and others.

A composite volume, the first portion of which (pp. 1-78, old foliation 1-38), written in the early eighteenth century, contains selections from Flores poetarum, triads, englynion, the divisions of Wales (pp. 29-33), cywyddau, poems in free metre, and an incomplete table of the contents of the latter portion of the volume (pp. 57-59). The second part of the volume (pp. 79-406, old foliation 1-245 with gaps) has been neatly written in two or more hands, one of the seventeenth century and the others of the early eighteenth century. It contains Welsh poems in strict and free metres from the fifteenth to the eighteenth centuries, many of them either of Anglesey interest or written by Anglesey poets, particularly Lewis Môn, Sion Brwynog and John Griffith of Llanddyfnan.
Among miscellaneous items are copies of the Articles of Agreement between the Parliamentary Commissioners and the inhabitants of Anglesey, 1648 (pp. 295-296); Sir Edward Trevor's riddle (p. 312); and a short bardic grammar (pp. 358-362).

A letter, in English, from Robert Vaughan of Hengwrt to James Ussher, archbishop of Armagh, concerning the dating of various historical events (pp. 1-44); and cywyddau and awdlau of Tudur Penllyn, Ieuan Tudur Penllyn and Dafydd Nanmor in the hand of Robert Vaughan (pp. 45-171).

Llawysgrif, [17 gan., canol], yn ôl pob tebyg yn llaw William Maurice, Llansilin, yn cynnwys barddoniaeth gaeth Gymraeg, cywyddau gan mwyaf, o waith o leiaf chwech ar hugain o feirdd. = A manuscript, [mid-17 cent.], probably in the hand of William Maurice, Llansilin, containing Welsh strict-metre poetry, mostly cywyddau, by at least twenty-six poets.
Priodolir y cerddi i'r beirdd canlynol: Tho[mas] Prys (ff. 1, 8-9), Y Meister Sion Tudur (f. 1 recto-verso), Sr. Gruffydd Owen (ff. 1 verso-2 verso, 5 verso-6 verso, 10 recto-verso, 24 verso-25), y Bedo Brwynllys (ff. 2 verso-3), Bedo Aryrddrem (ff. 3, 21 verso, 26), Huw Arwystli (ff. 3 recto-verso, 26-27), Rys Cain (f. 4 recto-verso), Morys Dwyfech (ff. 5 recto-verso, 25-26), Sion Phylip (ff. 6 verso-7), Sr Dafydd Owain (ff. 7 verso-8), W[illia]m llŷn (ff. 9 recto-verso, 12 verso-13), Sr Phylip Emlyn (ff. 10 verso-11), Ifan Dyfi (ff. 11-12), Dafydd ap Gwilim (ff. 12 recto-verso, 16, 17 verso-18, 20-21, 27 recto-verso, 28-29 verso, 30 verso), Sion Cain (ff. 13 verso-14), y Meistr Hughe Machno (ff. 14-15), Einion ab Gwalchmai (f. 15 verso), Sion Mowddwy (f. 16 verso), Tudur Aled (f. 17 recto-verso), Dafydd ap Edmwnt (ff. 18 verso-19), Dafydd Nanmor (f. 19 recto-verso), Gwillim tew brydydd (ff. 19 verso-20), Lewis Môn (f. 21), William Cynwal (ff. 21 verso-23, 24), 'Mr Roberts or tu hwnt ir môr' [Dr Gruffydd Robert, Milan] (ff. 23 verso-24) a Simwnt Vychan (ff. 27 verso-28, 30). Mae ambell i gerdd yn ddienw (ff. 4 verso-5, 7 recto-verso, 16, 18 recto-verso, 22 recto-verso). Mae yna nodiadau o ramadeg barddol, yn trafod yr englyn unodl union a'r englyn unodl cyrch, ar f. 30. Ceir nodiadau yma ac acw, mewn llaw o'r ddeunawfed ganrif, yn awgrymu dyddiadau blodeuo'r beirdd (e.e. f. 3: '1500 medd Thomas Richards'); daw y rhain o restr yn Thomas Richards, Antiquae Linguae Britannicae Thesaurus... (Bryste, 1753). = The poems are attributed to the following: Tho[mas] Prys (ff. 1, 8-9), Y Meister Sion Tudur (f. 1 recto-verso), Sr. Gruffydd Owen (ff. 1 verso-2 verso, 5 verso-6 verso, 10 recto-verso, 24 verso-25), y Bedo Brwynllys (ff. 2 verso-3), Bedo Aryrddrem (ff. 3, 21 verso, 26), Huw Arwystli (ff. 3 recto-verso, 26-27), Rys Cain (f. 4 recto-verso), Morys Dwyfech (ff. 5 recto-verso, 25-26), Sion Phylip (ff. 6 verso-7), Sr Dafydd Owain (ff. 7 verso-8), W[illia]m llŷn (ff. 9 recto-verso, 12 verso-13), Sr Phylip Emlyn (ff. 10 verso-11), Ifan Dyfi (ff. 11-12), Dafydd ap Gwilim (ff. 12 recto-verso, 16, 17 verso-18, 20-21, 27 recto-verso, 28-29 verso, 30 verso), Sion Cain (ff. 13 verso-14), y Meistr Hughe Machno (ff. 14-15), Einion ab Gwalchmai (f. 15 verso), Sion Mowddwy (f. 16 verso), Tudur Aled (f. 17 recto-verso), Dafydd ap Edmwnt (ff. 18 verso-19), Dafydd Nanmor (f. 19 recto-verso), Gwillim tew brydydd (ff. 19 verso-20), Lewis Môn (f. 21), William Cynwal (ff. 21 verso-23, 24), 'Mr Roberts or tu hwnt ir môr' [Dr Gruffydd Robert, Milan] (ff. 23 verso-24) and Simwnt Vychan (ff. 27 verso-28, 30). A few further poems are anonymous (ff. 4 verso-5, 7 recto-verso, 16, 18 recto-verso, 22 recto-verso). There are notes from a bardic grammar, discussing the 'englyn unodl union' and the 'englyn unodl cyrch', on f. 30. Notes added here and there, in an eighteenth-century hand, give suggested floruit dates for the poets (e.g. f. 3: '1500 medd Thomas Richards'); these are taken from a list in Thomas Richards, Antiquae Linguae Britannicae Thesaurus... (Bristol, 1753).

A manuscript containing poetry by Guto'r Glyn, Siôn Tudur, Wiliam Llŷn, Gruffydd Phylip and others.

A volume of popular Welsh poems on religious and scriptural themes written c. 1673-1674 by James Phillipp(es), with additions made a generation later by Phillipp James. The poems belong to the type of verse known in Cardiganshire as 'halsingod'. Linguistic evidence suggests that the authors were natives of East Carmarthenshire.

A volume of 'englynion' entitled 'llyfr wiliam Siôn o fryn saeth', and partly in the hand of David Jones ('Dewi Fardd'). Many of the 'englynion' are unattributed, and the few poets represented in the volume are William Cynwal, Lewis Glyn Cothi, Ellis ap Llew[elyn], Rhys ap Niclas, Sion Philip, Dr. Sion Siengcin, Lewis Menai, Owen Jones ('o dref machynlleth'), Sion Tudur, Thomas Eufan, Ed'd ap Raff, Wm. Sion Wyn, Da'dd Siengcin, Iolo Goch, Dafydd Jones ('o Drefriw, tan yr yw', 'Dewi Fardd', 'Dewi Sion'), Moris Powel, Hyw Morris ('ar ei glafwely'), William Philip, Owen Griffydd, Mr. Mredydd Wyn ('o lanyfudd'), and Rowlant Preis. Also bound in the volume are a list of texts of sermons, 1720-1724, preached partly by Mr. Anwill, Mr. Nanney, and Mr. Thomas; and fragments of printed almanacs, among them being that of [Thomas Jones], 1686, and that of [John Jones, 'Philomath'], 1739, both published in Shrewsbury.

Notes in the hand of Chancellor Wynne, comprising notes on Anglesey and on Welsh genealogies (pp. 1-8); a genealogical table of the pedigree of Edward Wynn of Bodewryd (pp. 9-15); abstracts of deeds relating to Bodewryd and Tyndryvol, and copies of papers relating to lawsuits (pp. 17-90); some memoirs relating to Chwaen wen and Bodowir (pp. 91-98); and biographical notes of some members of the Bodewryd family (pp. 99, 107-110).
Also included is a copy, in the hand of Hugh Hughes, of a cywydd, 'Marwnad Dd. ap Rhees ap Lle'n ap Gr. Tad Hugh Gwynn Bodewryd a Phirse Llwyd Gwredog' by Sion B[rwynog] (pp. 15-16).

'Cywyddau' and other poems by John Vaughan, Wiliam Phylip, Siôn Phylip, Sion Dafydd ap Siencyn, Edwart ap Rhys, Raff ap Robert, Dafydd Nanmor, Gruff[u]dd Gr[y]g, Simwnt Fychan, Richard Phylip, Siôn Tudur, Llywelyn Goch ap Meurig Hen, Rhys Cain, Gruffudd Hiraethog, Dafydd ap Gwilym, Wiliam Llŷn, Syr David Owen, Dafydd Llwyd ap Llywelyn ap Gruffudd, Thomas Prys, Siôn Mowddwy, Wiliam Cynwal, Edmwnd Prys, Siôn Cain, Ellis Wynne, Ellis Rowland, Huw Llwyd Cynfal, Ffowc Prys, Iolo Goch, Dafydd Epynt, etc.

Cyfrol yn cynnwys barddoniaeth Gymraeg a chynghorion meddygol a ddangoswyd, yn ôl nodyn (f. 63 verso) gan John Jones (Jac Glanygors), i John Edwards (Siôn Ceiriog) yn Llundain, 11 Gorffennaf 1790. = A volume containing poetry in Welsh and medical recipes shown, according to a note (f. 63 verso) by John Jones (Jac Glanygors), to John Edwards (Siôn Ceiriog) in London, 11 July 1790.
Mae'r gyfrol yn cynnwys cywyddau ac englynion o'r 16 gan. hyd at 18 gan., gan gynnwys gweithiau Gruffydd ap Ieuan ap Llywelyn Fychan, 'Syr' Dafydd Owain, Siôn Tudur, Simwnt Fychan, Thomas Prys o Blas Iolyn, William Phylip, ac Ellis Rowland o Harlech (ff. 1-41), ac englynion Saesneg (f. 1 verso); ceir rysáit llawfeddygol ar f. 7, cynghorion meddygol rhwng ff. 41 verso a 63 verso, a nodyn, 28 Gorffennaf 1790, gan David Samwell (Dafydd Ddu Feddyg) ar f. 64; fe nodir rhai o'r cerddi a'r ryseitiau ar dudalen gynnwys (f. 66 verso). = The volume comprises 'cywyddau' and 'englynion' from 16 cent. to 18 cent., including the works of Gruffydd ap Ieuan ap Llywelyn Fychan, 'Syr' Dafydd Owain, Siôn Tudur, Simwnt Fychan, Thomas Prys of Plas Iolyn, William Phylip, and Ellis Rowland of Harlech (ff. 1-41), and English poetry written in the 'englyn' metre (f. 1 verso); a veterinary recipe is included on f. 7, medical recipes between ff. 41 verso and 63 verso, and a note, 28 July 1790, by David Samwell (Dafydd Ddu Feddyg) on f. 64; some of the poetic works and recipes are listed in a contents' page (f. 66 verso).

Copi o Jonathan Hughes, Bardd, a Byrddau Amryw, Seigiau; neu, Gasgliad o Gynghanedd sef Carolau a Cherddi a Chywyddau (Amwythig: Stafford Prys, 1778; ESTC T140501, Libri Walliae 2526), gyda cherddi wedi eu hychwanegu mewn llawysgrif tu mewn i'r clawr blaen ac ar y dail rhwymo (tt. i-vi, 376-382), yn bennaf yn llaw William Samuel, [18 gan., hwyr]. = A copy of Jonathan Hughes, Bardd, a Byrddau Amryw, Seigiau; neu, Gasgliad o Gynghanedd sef Carolau a Cherddi a Chywyddau (Shrewsbury: Stafford Prys, 1778; ESTC T140501, Libri Walliae 2526), with Welsh poetry added in manuscript inside the front cover and on the fly-leaves (pp. i-vi, 376-382), mostly in the hand of William Samuel, [late 18 cent.].
Ymysg y tair cerdd ar ddeg a ychwanegwyd, mae dwy bennill gan William Samuel (tt. v, vi), ['Cerdd y Pren Almon'] gan Owen Griffith, [Llanystumdwy] (tt. 376-381), englyn gan Rhys Jones o'r Blaenau (t. 381) a phennill cyntaf cerdd [gan Dafydd Williams] (t. 382). Ceir mân gywiriadau ac arnodiadau ar tt. 5, 27, 111, 150, 182, 184, 202, 286, 358, 360, 367 a 369. Mae toriad papur newydd, 17 Ebrill 1928, ynglŷn â Jonathan Hughes wedi ei phastio i mewn ar. t. viii. = Amongst the thirteen additional poems are two verses by William Samuel (pp. v. vi), ['Cerdd y Pren Almon'] by Owen Griffith, [Llanystumdwy] (pp. 376-381), an englyn by Rhys Jones, Blaenau (t. 381) and the first verso only of a poem [by Dafydd Williams] (t. 382). There are minor corrections and annotations on pp. 5, 27, 111, 150, 182, 184, 202, 286, 358, 360, 367 and 369. A newspaper cutting, 17 April 1928, relating to Jonathan Hughes is pasted in on p. viii.

A volume in the hand of J. H. Davies containing transcripts of Welsh poetry, mainly 'englynion', lists of the compositions of Welsh poets of the 14th-16th centuries (titles and first lines) and a few miscellaneous notes. Nearly all the contents are copied from Jesus College MSS lxxxviii, ci, cxxxviii, cxxxix (R.W.M., Vol. II, Part I, Jesus College MSS 18, 17, 16, 14); the main source of the poetry is Jesus College MSS lxxxviii. The first three pages contain extracts from Ashmolean 847. There is some material from printed sources, including a plan (p. 166) of the British encampments and the mines worked by the Ancient Britons between Rheidol and Dovey, probably copied from J. G. Williams: A short account of the British Encampments lying between the rivers Rheidol & Llyfnant ... (Aberystwyth, 1866).