G.T.: Gwilym Tew (Glam.), c. 1450.
Gu.O., Gut.O.: Gutun Owain (Denb.), fl. 1450–90.
G.V.: Gruffudd Vychan, c. 1320.
G.Y.C.: Gruffudd ab yr Ynad Coch, c. 1280.
H.A.: Huw Arwystl c. 1550.
H.C.Ỻ.: Huw (or Hywel) Cae Llwyd, c. 1480 [Ỻ r. p. 428 footn. for 1525 read 1475].
H.D.: Huw Dafi, or Hywel ap Dafydd ab Ieuan ap Rhys (Brec.), c. 1480.
H.K.: Hywel Kilan (l ≡ l-l) (Llŷn?), c. 1480.
H.M.: Hugh Maurice (Denb.), 1622–1709; ref. to Eos Ceiriog…2 vols. Wrexham, 1823.
H.O.G.: Hywel ab Owain Gwynedd, Prince of the House of Gwynedd, d. 1170.
H.R.: Hywel Rheinallt, c. 1480.
H.S.: Hywel Swrdwal (Montgomerysh.), c. 1450; ref. to Gwaith Barddonol Hywel Swrdwal a’i Fab Ieuan, ed. by J. C. Morrice, Bangor Welsh MSS. Soc., 1908.
I.B.H.: Ieuan Brydydd Hir (Merioneth), c. 1450.
I.C.: Iorwerth ab y Cyriawg, c. 1360.
I.D.: Ieuan Deulwyn (Carm.), fl. 1460–80; ref. to Gwaith Ieuan Deulwyn, ed. by Ifor Williams, Bangor Welsh MSS. Soc. 1909.
I.F.: Iorwerth Fynglwyd (Glam.), c. 1490.
I.G.: Iolo Goch (Denb.), fl. 1370–1405; ref. to Gweithiau Iolo Goch…Gan Charles Ashton, Cymmrodorion Soc., 1896.
I.H.S.: Ieuan ap Hywel Swrdwal, c. 1470; ref. as for H.S., q.v.
I.Ỻaf.: Ieuan Llavar, c. 1590.
Io.G. = I.G.
I.R.: Ieuan ap Rhydderch ab Ieuan Llwyd, c. 1420.
I.T.: Ieuan Tew o Gydweli, c. 1460 (often confused with the later, and lesser, Ieuan Tew who graduated at the Caerwys Eisteddfod of 1568).
L.G.C.: Lewis Glyn Cothi, fl. 1440–80; ref. to Gwaith Lewis Glyn Cothi…Oxford 1837.
L.M.: Lewis Morris (Llywelyn Ddu o Fôn), 1701–65.
L.Môn: Lewis Môn, c. 1500.
L.Mor.: Lewis Morgannwg, c. 1520.
Ỻ.: Llawdden (Llandeilo, i.mss. 320), c. 1460.
Ỻ.G.: Llywelyn Goch Amheurig Hên, c. 1380.
M.: Meilyr (Anglesey), c. 1137.
M.B.: Madog Benfras, c. 1380.
M.D.: Madog Dwygraig, c. 1370.
M.K.: Maurice Kyffin; ref. to Deffynniad Ffydd Eglwys Loegr 1595, reprint ed. by Wm. Pochard Williams, Bangor 1908.
M.Ỻ.: Morgan Llwyd o Wynedd, 1619–1659; ref. to Gweithiau Morgan Llwyd o Wynedd, i ed. by Thomas E. Ellis, Bangor 1899; ii ed. by John H. Davies, Bangor 1908.
M.R.: Maredudd ap Rhys, c. 1440.