Owain Glyndŵr were leaving their studies to join Owain, and Welsh labourers and craftsmen were abandoning their employers in England and returning to Wales. Owain could also draw on Welsh troops seasoned by the English campaigns in France and Scotland. Hundreds of Welsh archers and experienced men-at-arms left English service to join the rebellion. In 1404, Owain held court at Harlech and appointed Gruffydd Young as his Chancellor. Soon afterwards, he called his first Parliament (or or "gathering") of all Wales at Machynlleth, where he was crowned Prince of Wales and announced his national programme. He declared his vision of an independent
Richard Beauchamp, 13th Earl of Warwick military action in Wales, defending against a Welsh rebellion led by Owain Glyndŵr. On 22 July 1403, the day after the Battle of Shrewsbury, he was made a Knight of the Garter. In the summer of 1404, he rode into what is today Monmouthshire at the head of a force. Warwick engaged Welsh forces at the Battle of Mynydd Cwmdu, near Tretower Castle a few miles northwest of Crickhowell – nearly capturing Owain Glyndwr himself, taking Owain's banner, forcing the Welsh to flee. They were chased down the valley of the River Usk where they regrouped and turned the tables