"Written at Hereford the said Wednesday at night.
Glyndwr, as soon as he heard of the disaster on the Monnow, pushed up fresh forces under his brother Tudor to meet the fugitives from Grosmont, with a view to wipe out, if possible, that crushing defeat. What strength they got, if any, from Rhys Gethin's scattered army there is no evidence, but in less than a week they encountered the Prince himself advancing into Wales with a considerable force, and at Mynydd-y-Pwll-Melyn, in Brecon, received a defeat more calamitous than even that of Grosmont. Fifteen hundred of the Welsh were killed or taken prisoners. Among the slain was Owen's brother Tudor himself; and so like the chief was he in face and form that for some time there was much rejoicing, and the news was bruited about that the dreaded Glyndwr was in truth dead. The spirits of the English were sadly damped when the absence of a wart under the left eye, a distinguishing mark of Glyndwr, proclaimed that their joy was premature, and that it was the dead face of his younger brother on which they were gazing. Among the prisoners, however, was his son Gryffydd, who was sent by the Prince to London and confined in the Tower, statements of money allowed for his maintenance there appearing from time to time on the Rolls. Gryffydd's (Griffin he is there called) fellow-prisoner is Owen ap Gryffydd, the son probably of the valiant Cardiganshire gentleman whom Henry quartered in 1402. A year later the young King of Scotland, whose life was safer there, no doubt, than in his own country, was the companion of Glyndwr's son. The Iolo manuscript before mentioned tells us:
"In 1405 a bloody battle attended with great slaughter that in severity was scarcely ever exceeded in Wales took place on Pwll Melin; Gryffyth ap Owen and his men were taken and many of them imprisoned, but many were put to death when captured, whereupon all Glamorgan turned Saxon except a small number who followed their lord to North Wales."
These two severe defeats were a great blow to Owen's prestige. They caused numbers of his adherents in South Wales to fall away and to seek that pardon which the King, to do him justice, was at all times very free in extending to Welshmen. Indeed, it would almost seem as if he himself secretly recognised the fact that they had much justice on their side and were rebels rather in name than in actual fact.