He had destroyed the houses and strong places of all Welshmen who had not taken up arms at his orders, and had closely blockaded Carnarvon.

He marched to Bangor, levelled the cathedral, and that of Saint Asaph, by fire, burnt the episcopal palaces and canons' houses.

So formidable did he become that the king issued writs, to the lieutenants of no fewer than thirty-four counties, to assemble their forces at Lichfield, to crush Glendower.
The latter had now taken the offensive, and advanced towards Hereford, and carried fire and sword through Mortimer's lands.

Sir Edmund gathered his own and his nephew's tenants and retainers, from Herefordshire and Radnorshire, and advanced against Glendower.

The armies met on the 22nd of June, 1402, at a short distance from Knighton.