A manuscript in two volumes containing a corpus of Welsh strict-metre verse consisting almost entirely of 'cywyddau', and a few Welsh prose items. The foliation of the 'text' (original f. 1 missing, original ff. 2-21 renumbered 1-20, a previously unnumbered folio between original ff. 21-2 now f. 21, ff. 22-623 as originally numbered with 75 twice and 265 and 577 missed out) is continuous, and the division into vol. I (ff. 1-300), now NLW MS 13061B, and vol. II (ff. 301-623), now NLW MS 13062B, occurs in the middle of a poem. Unnumbered leaves of later origin than those of the text have been inserted at the beginning and end of each volume. The manuscript, sometimes referred to as 'Y Byrdew Mawr', is in the hand of Thomas ab Ieuan of Tre'r-bryn, parish of Coychurch, co. Glamorgan, the scribe of NLW MSS 13063B, 13069B, and 13085B, and was probably transcribed in the last quarter of the seventeenth century, partly from the manuscripts of an earlier Glamorgan copyist, Llywelyn Siôn (see TLLM, tt. 95, 167-73, 218-19, 268; IM, tt. 87, 154, 264; and IMCY, tt. 81, 175). It was probably presented to Edward Williams ('Iolo Morganwg') by the copyist's grandson also named Thomas ab Ifan (see TLLM, tt. 170, 268). The contents include (revised foliation) :- 1 recto - verso, rules re interpreting the significance of dreams in relation to the phases of the moon (incomplete); 1 verso-8 recto, another set of rules (183) for interpreting dreams ('Deall braiddwydon herwydd Daniel broffwyd'); 8 recto-11 recto, a sequence of forty-eight 'englynion' entitled 'Englynion rhwng Arthur a Liflod i nai' (see The Bulletin of the Board of Celtic Studies, vol. II, pp. 269-86); 11 recto-verso, a poem attributed to 'Taliesin ben bayrdd'; 12 recto-15 verso, prognostications including 'Arwyddion kyn dydd brawd', and four 'englynion'; 16 recto-21 recto, 'Llyma anian diwarnodav y vlwyddyn o gwbl oll'; 21 verso, prognostications re birthdays; and 22 recto-623 verso, poems ('cywyddau' unless otherwise indicated) by Iorwerth Vynglwyd (17), Ieuan Rydd, Tydur Aled (12), Howel ap Rainallt (3), Mathav ap Lle'n Goch, Lewys y Glynn (7), Davydd ap Edmwnt (5), Siôn y kent (24), Davydd llwyd (2), Risiart Iorwerth (4), Llawdden (or Ieuan Llawdden) (6), Davydd Nanmor (5), Iolo Goch (8), Ieuan Daelwyn (13), Lewys Morgannwg ( 18), Thomas Lle'n (5, also 1 'englyn'), Howel ap Davydd ap Ieuan ap Rys (17), Ieuan Tew Bry[dy]dd Ievank (3), Huw Kae Llwyd (8), Ieuan Dyvi (2), Ieuan ap Howel Swrdwal (2), Davydd Llwyd Lle'n ap Gr' (3), Risiart ap Rys Brydydd (3), Tomos Derllysg (4), Gyttyn Kairiog, Ieuan Llwyd ap Gwilym, Ieuan Rydderch ap Ieuan Llwyd (3), Robert Laia, Ieuan Du Bowen Lle'nn ap Howel ap Ieuan ap Gronw (7), Rys Goch 'o Vochgarn', Ieuan Brydydd Hir, Gytto'r Glynn (25), Maredydd Brydydd, Howel Swrdwal (3), Thomas Lle'n Dio Powell (2), William Kynwal, Siôn Tydyr (7), Hyw Davi 'o Wynedd' (3), Huw Davi, Tomas ap Siôn Kati (2), Syr Rys 'o Garno', Syr Lewys Maudw, Syr Phylip Emlyn (2), Huw Lewis, Davydd Ddu Hiraddug, Davydd ap Gwilym (10), Bedo Aurddrem, Morys ap Howel, Ieuan Tew Brydydd (9), Siôn Brwynog, Harri ap Rys ap Gwilym (3), Morys ap Rys, Davydd Benwyn (11), Rydderch Siôn Lle' nn, Sils ap Siôn (3), Lle'n ap Owain, Syr Huw Robert L'en (3), Davydd ap Rys, Thomas Gryffydd, Siôn Phylip, Gwyrfyl verch Howel Vychan, Morgan ap Howel (or Powel) (4), Lle'n Siôn (8), Gryffydd Gryg (5), Maredydd ap Rys, Tydur Penllyn (2), Gronw Wiliam, Bedo Phylip Bach (4), Siôn Mowddwy (11), Rogier Kyffin (4), Wiliam Gryffydd ap Siôn (2), Hyw Dwnn, Lewys Môn (5), Wiliam Egwad (2), Ieuan Du'r Bilwg (2), Rys Brydydd, Daio ap Ieuan Du or Daio Du o Benn Adainiol (3), Gwilim Tew Brydydd (10), Rys Brychan, Maredydd ap Roser, Daio Lliwiel, Lle'nn Goch y Dant, Gryffydd Davydd Ychan (2), Syr Gryffydd Vychan, Lang Lewys, Rys Llwyd Brydydd, Meistr Harri Le'n ( 2), Siôn ap Howel Gwyn (2), William Llvn (5), Ieuan Gethin (ap Ieuan ap Llaison) (3), Gwilim ap Ieuan Hen, Ieuan ap Hyw, Gryffydd Hiraethog (5), Rys Pennarth, Davydd Llwyd Mathav (4), Davydd Emlyn, Davydd Goch Brydydd 'o Vyellt' (2), Rys Nanmor (3), Risiart Vynglwyd (2), Watkin Powel (6), Mairig Davydd (4), Ieuan Rauadr, Owain Gwynedd, Morgan Elfel, Syr Davydd Llwyd (3), Ieuan Thomas (4), Rys Goch 'o Eryri' (3), Lle'n vab Moel y Pantri (2), Syr Davydd ap Phylip Rys, Rys Trem, Siankin y ddyfynog (3), Morys ap Lle'nn, Risiart Thomas, Lle'nn Mairig, Gryffydd Llwyd ap Davydd ap Einon, Gryffydd Llwyd ap Einon Lygliw, Hopgin Thom Phylip, Edward Davydd (4), Ieuan Du Davydd ap Owain, Bedo Brwynllys, Thomas ap Rys 'o Blas Iolyn', Thomas Wiliam Howel, Davydd ap Ieuan Ddu, Syr Owain ap Gwilym, Rys ap Harri 'o Euas' (2), Edwart ap Rys, Davydd Manuel 'o Sir Drefaldwyn', SiamsThomas, Thomas Brwynllys, and Swrdwal. The unnumbered folios at the beginning of each volume contain a list of the contents of the volume giving, in the case of the poems, the name of the poet, in a hand bearing a strong resemblance to that of William Owen Pughe, and the title of the poem, in the hand of Edward Williams. The folios at the end of the first volume contain an index of the bards whose works appear in both volumes. This is possibly in the hand of Hugh Maurice, tanner and copyist. On one of the added folios at the end of the second volume is a poem to the Reverend John Jones, D.D., dean of [the cathedral church of] Bangor. Both volumes contain marginalia in the hand of Edward Williams.
