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.

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).

An incomplete miscellany, in the form of three unbound volumes, of free- and strict-metre poetry (including illustrative extracts), compiled by David Thomas ('Dafydd Ddu Eryri') under the title of 'Golwg a'r Parnassus, a Helicon, Sef, Casgliad neulltuol, neu Bigion Dewisol Allan o Waith Prif feirdd neu Brydyddion yr oesoedd, sef y Rhannau hyny o'u Gwaith na ymddangosodd yn argraphedig Hyd yn hyn ond mewn hen Sgrifeniadau, yn Englynion A chywyddau. yn Ddwy Rann; un yn Ddigrifol ar llall yn ddifrifol. O Gascliad, Dewi, ab Thomas, Waunfawr. A Sgrifenwyd yn y flwyddyn 1781'. The preface ('Rhagymadrodd at y Darllenydd') indicates both the period and partly the source of the volume: 'Y Darnau canlynol o Brydyddiaeth a Sgrifennwyd Gennyf yn fy Ieuenctyd, Pan ddechreuais Gyntaf Gael blas, ar farddoniaeth Reolaidd Ac yn ol fy nhŷb i, y Pryd hwnnw, maent yn Brif orchestwaith, Pigion, neu oreuon, Gwaith yr hen Feirdd ... Yr a adsgrifennais wrth ymdeithi[o] yn ddamweiniol, heibio'r lleoedd yr oeddynt iw gweled fel y Gwelwch yn Enwau'r Eglwysydd'. The poets represented include Rhichard Phylip; Maredudd ap Rhys; David Thomas ('Dafydd Ddu Eryri'); Hugh Hughes ('Y Bardd Coch o Fôn') (1766); Huw Morys; Siôn Cent; William Phylip; Elis Roberts; Dafydd ap Gwilym; Siôn Phylip; Bedo Brwynllys; Tudur Aled; Gruffudd Hiraethog; Siôn Brwynog; Siôn Tudur; Edward Morys; Owen Gruffydd; and Siôn Mawddwy. The titles include 'Englynion i Sir feirionydd'; 'Englynion Iw gosod ar fedd Huw Jones o Langwm ...'; and 'Englyn i Hugh Lloyd Cynfel'. Additions in other hands include some music scores of carol tunes and calligraphic exercises.

A volume of transcripts of poetry, mainly 'cywyddau' and 'englynion', by Iowerth Fynglwyd, William Llŷn, Huw Cae Llwyd, Gwilym ap Sefnyn, Dafydd Nanmor, Thomas Prys, Syr Dafydd Trefor, Aneurin Gwawdrudd ('Anearan Gwowdrudd'), Rhys Pennardd, Iolo Goch, Gutun Ceiriog, Siôn Mawddwy, Dio ap Ifan Du, Rhys Goch Glyndyfrdwy, Dafydd ap Edmwnd, Dafydd Ddu o Hiraddug, Philip John Philip, Siôn Philip, Owain Gwynedd, Ieuan Brydydd Hir, Siôn Cent, David Jones, Rhys Wynn, Siôn Tudur, Dafydd ap Gwilym, Dafydd Llwyd ap Llywelyn ap Gruffudd, Meredydd ap Rees, Llywelyn ap Gutun, Syr Owain ap Gwilym, Griffith Philip, Rowland Vaughan, Richard Philip, Edmwnd Prys, Robin Ragett, Tudur Aled, John Prichard Prys, Robert Klidro, Ellis Rowland 'o Harlech', Hugh Llwyd 'o Gynfal', Huw Morris, Lewis Morris, Mr. David Roberts, Rice Lloyd, Moris ap Robert, Bala, and Thomas Jones, Orsedd Las. The greater part of the volume was written in the early eighteenth century. Among slightly later hands at the end of the volume is that of William Jones of Orsedd Las. At the end of the volume is a letter from a Welsh emigrant, written from Delaware, 21 September, 1828.

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.

'Cywyddau' and other poetry by Gruffudd Hiraethog, Bedo Phylip Bach, Lewis Glyn Cothi, Bedo Brwynllys, Tudur Aled, Robin Ddu, Sion Phylip, R-- M--, Sion Tudur, Wiliam Llŷn, Ieuan Dew Brydydd, Llywelyn ap Gutun, Edmwnd Prys, Richard Cynwal, Syr Dafydd Trefor, Gruffudd ap Tudur ap Hywel, Dafydd ap Rhys ab Evenni [?o Fenai or o'r Fenni], Huw Llifon ('Clochydd Llanefydd'), Lewis Lloyd, Lewis ab Edward, Iolo Goch, Dafydd Nanmor, Maredudd ap Rhys, Sion Cent, Siencyn ab Ieuan ap Bleddyn, Sion Gwyn ap Digan, Syr Phylip o Emlyn, Ieuan Llwyd Brydydd, Dafydd ap Gwilym, Sion Ceri, Robert Dafydd Llwyd, Ieuan ap Rhydderch, Lew[y]s Môn, Huw ap Dafydd, Iorwerth Fynglwyd, Huw ap Tomos, Huw Machno, Simwnt Fychan, Rhys Wyn ap Cadwaladr, Wiliam Cynwal, Thomas Prys, Dafydd Llwyd ap Llywelyn ap Gruffudd, Dafydd ab Edmwnd, Gutun Owain, Gruffudd ab Ieuan ap Llywelyn Fychan, Gruffudd Llwyd ab Ieuan, Llywelyn Goch ap Meurig Hen, Raff ap Robert, Rhys Pennardd and Edwart ap Raff; englynion.

A transcript by William Jones ('Bleddyn'), Llangollen, formerly of Beddgelert, of 'cywyddau' and 'englynion' by Dafydd ap Gwilym, Iolo Goch, Dafydd ab Edmwnd, Tudur Aled, Guto'r Glyn, Tudur Penllyn, Syr Rhys o Garno, Sion Cent, Maredudd ap Rhys, Lewis Glyn Cothi, Llawdden, Robin Clidro, Sion Tudur, Wiliam Cynwal, Wiliam Llŷn, Edmwnd Prys, Simwnt Fychan, Sion Brwynog, Owain Gwynedd, Gruffudd ab Ieuan ap Llywelyn Fychan, Thomas Prys, Sion Prys ('o'r Gerddinen'), Edwart ap Raff, Rhys Ednyfed, Thomas Evans, Huw Arwystli, Watcyn Clywedog, Sion Dafydd Lâs [John Davies], Owen Gruffydd, Dafydd Gwyne, Dafydd Jones ('Ficer Llanfair Dyffryn Clwyd'), Gruffudd Hiraethog, Ieuan Deulwyn, Hywel ap Dafydd ab Ieuan ap Rhys, Inco Brydydd, Gruffudd Gryg, Ellis Rowland and Hywel ap Rheinallt; 'englynion'.

A seventeenth century transcript of 'cywyddau' by Rhys ap Rhys, Ieuan Brechfa, Syr Dafydd Trefor, Tudur Aled, Lew[y]s Môn, Siôn Tudur, Gruffudd Hiraethog, Huw Talai, Ieuan ap Hywel Swrdwal, Dafydd ap Hywel ab Ieuan Fychan, Ieuan Deulwyn, Robin Ddu, Deio ab Ieuan Du, Mathew Brwmffild, Guto'r Glyn, Lewis Glyn Cothi, Rhys Degannwy, Dafydd Nanmor, Gruffudd ap Gronw Gethin ('o lanvair talhayarn'), Wiliam Llŷn, Syr Owain ap Gwilym, Lew[y]s Morganwg (Llywelyn ap Rhisiart), Llawdden, Ieuan Gyfannedd, Dafydd Baentiwr, Gruffudd Gryg, Dafydd ap Gwilym, Dafydd ab Edmwnd, Gutun Owain and Dafydd Cowper.

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

Transcripts by Ioan Pedr and others of poems by Iolo Goch, Rhys ap Hywel [ap Dafydd], Dafydd Owain, Gruffudd Hiraethog, Siôn Cent, Catrin ferch Gruffudd ap Hywel ('o Lan Ddeiniolen'), Syr Phylip o Emlyn, Siôn Phylip, William ap Robert, Edmwnd Prys, Rhys Wyn ap Cadwaladr, Owain Gwynedd, Deio ab Ieuan Du, Tudur Penllyn, Tudur Aled, Dafydd [ap] Llywelyn ap Madog, Simwnt Fychan, Richard Cynwal, Siôn Cain, Dafydd Nanmor, Edwart Urien, Gruffudd Phylip, [Ifan] Tudur Owen, Dafydd Llwyd ap Wiliam [David Lloyd], Siôn M[a]wddwy, Siôn Brwynog, Richard Phylip, Dafydd Llwyd ap Hywel ap Robert, Dafydd ap Gwilym, Dafydd ab Edmwnd, Wiliam Cynwal, Thomas Prys, Robin Ddu, Richard Prise, Richard Owen ap Richard, Rhys ab Ednyfed, Dafydd Nanmor, Hywel ap Dafydd ab Ieuan [ap Rhys] and Bedo Hafes[b]; 'Trioedd Taliesin'; 'Y pedwar gwell ar hugain'; 'Tri thlws ar ddeg o frenin dlysau Ynys Brydain'; original poems and translations from French, German and Italian by Ioan Pedr, and a short note on the literature of Brittany.

Transcripts of Welsh poetry by Owen Williams, Waunfawr, 1859, including poems by Ieuan Tew Hynaf, Siôn Brwynog, Dafydd ab Ieuan ab Owain, Cadwaladr Cesail o'r Gesail Gyfarch, Dafydd Nanmor, Dafydd ab Edmwnd, William Llŷn, Rhys Cain, Simwnt Fychan, Iolo Goch, Robin Ddu, Ieuan Môn, Guto'r Glyn, Ieuan ap Madog ab Dafydd, Gruffydd Llwyd, Lewys Daron, Syr John [Siôn] Leiaf, Hugh Pennant, Rhys Nanmor, Siôn Dafydd Penllyn, Syr Dafydd Owain, Gruffydd ab Ieuan ab Llywelyn Fychan, Hywel Cilan, Siôn Tudur, Lewys Môn, Hywel Gethin, Ieuan ap Gruffudd Leiaf, Watcyn ap Rhisiart, Hywel ap Rheinallt, Mathew Bromfield, Watcyn Clywedog and Adda Fras; with a note of the sources of 'Llyfr Mr. Lloyd Ffestiniog' then (1859) in the possession of David Williams, solicitor, Bron Eryri.

A typescript essay entitled 'Casgliad o weithiau Sion Brwynog, gyda nodiadau hanesyddol a beirniadol' by the late the Reverend Gilwym H[ywel] Jones, Welsh Presbyterian minister, Blaenclydach, co. Glamorgan. The essay, under the pseudonym of 'Emrys', was awarded the prize at the National Eisteddfod at Holyhead, 1927, and pasted into the volume is a typescript copy of the adjudication of Professor Sir John Morris Jones and Professor Henry Lewis.

'Cywyddau' and other poems by Rhys Gray, Hywel Cilan, Huw ap Huw, Sion ap Hywel ap Llywelyn Fychan, Guto'r Glyn, Lewis Glyn Cothi, Dafydd ap Gwilym, Ieuan Dew Brydydd, Ieuan Brydydd Hir, Wiliam Llŷn, Iolo Goch, Gruffudd Gryg, Syr Dafydd Trefor, Dafydd Nanmor, Wiliam Cynwal, Lewis Menai, Sion Tudur, Tudur Penllyn, Gruffudd Hiraethog, Sion Brwynog, Dafydd ab Edmwnd, Lewis Môn, Llywelyn Moel y Pantri, Sion Dafydd Rhys, Hywel Rheinallt, Rhys Goch Eryri, Llywelyn Goch ap Meurig Hen, Ieuan Gethin ab Ieuan ap Lleision, Lewis Morganwg, Huw Llwyd Cynfal, Sion Phylip, Richard Phylip, Tudur Aled, John Davies, Owain Gwynedd and Sion Cent.

A composite volume containing transcripts by Edward Williams ('Iolo Morganwg') of Welsh poems, mainly strict-metre verse in the form of 'cywyddau', attributed to Syr Dafydd Owain, Huw Dafydd Llwyd, Ieuan ap Hywel Swrdwal, Llawdden, Dafydd Llwyd Matthew, Siôn Mowddwy, Rhobin Ddu 'o Fôn', Siôn Tudur, Syr Dafydd Llwyd Fach or Syr Dafydd Llwyd Ysgolhaig, Lewis Glyn Cothi, Huw Pennant, Rhosser Cyffin, Person Llanberis, Dafydd ap Dafydd Llwyd, Thomas Prys, Rhisierdyn, Gutto'r Glynn, Meredydd ap Rhys, Rhys Goch Glyndyfrdwy, Siôn Brwynog, Thomas Celli, Llywelyn Goch ap Meuryg Hen, Rhys Cain 'o Groes Oswallt', Rhisiart Philip, Rhys Llwyd ap Rhys ap Rhiccart, Hywel ap Syr Mathew, Gruff. Hiraethog, Edmund Prys, Arch[d]diacon Meirionydd, Gruffudd Hafren, Rowland Fychan 'o Gaer Gai', Ieuan Llwyd Sieffre, Ieuan Tew Brydydd, Owain ap Llywelyn Moel, Lewys Môn, Dafydd Pennant, Rhys Goch ap Dafydd sef Rhys Goch Eryri, Tudur Aled, Ieuan Brydydd Hir, Siôn Philip, Lewis ab Edward Bencerdd, Wiliam Cynwal, Ieuan Deulwyn, Gruffudd ap Gweflyn, Lewys Menai, Dafydd Llwyd 'o Fathafarn', Dafydd ap Hywel, Ieuan ap Gruffudd Leiaf, Huw Arwystli, Rhys ap Llywelyn ap Gruffudd ap Rhys, Guttyn Owain, Hywel Dafydd ap Ieuan ap Rhys, Iolo Goch, Ieuan Llawdden, Wiliam Llyn, Gruffudd Gryg, Dafydd Llwyd ab Einion Lyglyw (or Gruffydd Llwyd ab Dafydd ab Einion Lygliw, or Dafydd ab Gruffydd Llwyd ab Einion Lygliw), Dafydd ab Gwilym, Lewys Morganwg (or Lewys Brydydd Hodnant), Rhisiart ap Rhys Llwyd, Iorwerth Fynglwyd, Thomas Derllysg, Dafydd, Abad diweddaf Margam, Siôn y Cent, Thomas Lleison 'o Gastell Nedd', Ieuan Du'r Bilwg, Llywelyn Moel y Pantri, Rhys Llwyd ab Rhys ab Rhisiart 'o Lan Haran', Ieuan Rudd, Gruffudd ap Ieuan ap Llywelyn Fychan 'o Lannerch Llyweni', Meredydd ap Rhosser, Tudur Penllyn, Dafydd ap Edmwnd, Ieuan Brechfa, Syr Owain ap Gwilym, Bedo Hafes, Syr Rhys o Garno, Dafydd Llwyd ab Llewelyn ab Gruffydd, Llywelyn ab Guttyn, Trahaiarn Brydydd Mawr, ? Iorwerth Beli, Llywelyn Goch y Dant, Wiliam Pywel 'o Gastell Madog', Dafydd y Coed, Ieuan Môn Hen, Gruffudd ab Gronw Gethin, Meyrig Dafydd, Wiliam Byrcinsha, Syr Dafydd Trefor, Bleddyn Siôn 'o Lancarfan', Casnodyn, Syr Rhys Offeiriad, Llywelyn ap Guttyn, Ieuan Gethin ab Ieuan ab Lleison, Syr Dafydd Jones, Ficcer Llanfair Dyffryn Clwyd, Ifan Llwyd, and Siôn ap Ffelpot. There are occasional notes on the poems and poets and on the source of the transcript.

A transcript by William Jones ('Bleddyn'), Llangollen of 'cywyddau' and 'englynion', etc. by Gwerful Mechain, Hywel Dafi [Hywel ap Dafydd ab Ieuan ap Rhys], Sion ap Philpot, Robert ap Dafydd Llwyd, Gruffudd Leiaf, Iorwerth Fynglwyd, Dafydd Llwyd ap Llywelyn ap Gruffudd, Sion ap Hywel ap Tudur, Huw Cae Llwyd, Lewis Daron, Bedo Brwynllys, Syr Rhys o Gar[no], 'Twm o'r Nant' [Thomas Edwards], 'Person Llangwm', Tudur Aled, Morys ap Hywel ap Tudur, Gruffudd Hiraethog, Huw Llwyd Cynfal, Ieuan Dew Brydydd, Dafydd ap Gwilym, Richard Cynwal, Huw Machno, Syr John [Sion] Leiaf, [Sir] Huw Pennant, Rhys Nanmor, Sion Dafydd Lâs [John Davies], Syr Dafydd Owain, Gruffudd ab Ieuan ap Llywelyn Fychan, Hywel Cilan, Sion Tudur, Lewis Môn, Hywel Gethin, Ieuan ap Gruffudd Leiaf, Watcyn ap Rhisiart, Hywel ap Rheinallt, Mathew Brwmffild, Guto'r Glyn, Watcyn Clywedog, Wiliam Llŷn, Wiliam Cynwal, Simwnt Fychan, Ieuan Llafar, Thomas Prys, William Vaughan, Huw Arwystli, Sion Phylip, Richard Phylip, Ieuan Dyfi, Lewis Menai, Rhys Goch Glyndyfrdwy, Llywelyn ap Gutun, Madog Leiaf and Ieuan ap Rhydderch, with 'englynion' by Dafydd Nanmor, Cadwaladr Ces[ai]l, Huw Ifan ap Huw ('o'r Brynbychan') and Siôn Ifan.

A notebook in the hand of David Evans, Llanrwst containing 'Y Llinell Gyntaf o bob Cerdd Cywydd a charol sydd yn yr hen Almanaciau ynghyd a henwau yr Awdwyr', i.e. a chronological list of first lines of poetry in strict and free metres published in Welsh almanacs from 1686 to 1786. The free metre poetry, 'carolau' and 'cerddi' are arranged separately under each author.

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 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.

Twelve letters (two damaged), with enclosures and part of another letter, 1869-84, to D. Silvan Evans from Edw[ar]d Hamer, Talywaun and Abersychan (Pontypool) and Llanidloes (the writer's wish to have perfect copies of two poems by Huw Arwystli [sic], the 'Llyfryddiaeth' [i.e. Llyfryddiaeth y Cymry], names of rivers in Montgomeryshire, etc., reference to the Mold Eisteddfod [1873] initiating the movement for the establishment of a National Library).

Thirty-two letters and one postcard, 1869-90, to D. Silvan Evans from Howel W[illiam] Lloyd (1816-93), Upper Chelsea and Kensington ('Y Marchog Crwydrad', mention of 'Llyfr Ceniarth', a manuscript containing poems by Huw Arwystli [sic], etc., bibliographical matters, his efforts to collect the poems of Guto'r Glyn, the addressee's dictionary).