Gruffudd Leiaf was a 15th-century
Welsh
Welsh may refer to:
Related to Wales
* Welsh, referring or related to Wales
* Welsh language, a Brittonic Celtic language spoken in Wales
* Welsh people
People
* Welsh (surname)
* Sometimes used as a synonym for the ancient Britons (Celtic peopl ...
poet, known almost exclusively from his works. He was reputed to descend from the royal family of Gwynedd.

Gruffudd Leiaf was born in Denbighshire, the son of Gruffudd Fychan, in turn son of Welsh knight Gruffudd ap Dafydd Goch,
who served on a 1352 jury and died c. 1370, buried at the church of
Betws-y-Coed
Betws-y-coed (; '' en, prayer house in the wood'') is a village and community in the Conwy valley in Conwy County Borough, Wales, located in the historic county of Caernarfonshire, right on the boundary with Denbighshire, in the Gwydir Forest ...
where his burial monument survives.
[Smith, J. Beverley, ''Llywelyn ap Gruffudd, Prince of Wales'' University of Wales Press, new edition, 2014, p. 579] The reputed father of this earliest Gruffudd, Dafydd Gogh of
Penmachno
Penmachno is a village in the isolated upland Machno valley, south of Betws-y-Coed in the county of Conwy, North Wales. The B4406 road runs through part of the village. The village is at the confluence of the Glasgwm and Machno rivers. It has ...
, was claimed by later genealogies to have been an illegitimate son of
Dafydd ap Gruffydd
Dafydd ap Gruffydd (11 July 1238 – 3 October 1283) was Prince of Wales from 11 December 1282 until his execution on 3 October 1283 on the orders of King Edward I of England. He was the last native Prince of Wales before the conquest of Wa ...
, who briefly reigned as the last native
Prince of Wales
Prince of Wales ( cy, Tywysog Cymru, ; la, Princeps Cambriae/Walliae) is a title traditionally given to the heir apparent to the English and later British throne. Prior to the conquest by Edward I in the 13th century, it was used by the rule ...
prior to his 1283 execution,
though no contemporary evidence of such a son survives. Gruffudd Fychan had nine children by his wife Wladus ferch Gruffudd of Llifon, Anglesey, including sons Hywel Coetmor, Rhys Gethin, Robert and Gruffudd Leiaf, who with their father were accused in 1390 of preventing non-Welsh-speaking parson William Broun from taking up his parish at Llanrwst, and they were summoned before king