Source.—Chronicle of Adam of Usk, edited by Sir E. Maunde Thompson, pp. 252, 253.

In the next year, on behalf of the crown of England claimed for the earl of March, a deadly quarrel arose between the King and the house of Percy of Northumberland, as kin to the same earl, to the great agitation of the realm...; and a field being pitched for the morrow of Saint Mary Magdalene (23rd July), the King, by the advice of the earl of Dunbar of Scotland, because the father of the lord Henry Percy and Owen Glendower were then about to come against the King with a great host, anticipating the appointed day, brought on a most fearful battle against the said lord Henry and the lord Thomas Percy, then earl of Worcester. And after that there had fallen on either side in most bloody slaughter to the number of sixteen thousand men, in the field of Berwick (where the King afterwards founded a hospice for the souls of those who there fell) two miles from Shrewsbury, on the eve of the said feast, victory declared for the king who had thus made the onslaught. In this battle the said lord Percy, the flower and glory of Christendom, fell, alas! and with him his uncle.... There fell also two noble knights in the King's armour, each made conspicuous as though a second King, having been placed for the King's safety in the rear line of battle. Whereat the earl of Douglas of Scotland, then being in the field with the said lord Henry, as his captive, when he heard victory shouted for King Henry, cried in wonder: "Have I not slain two King Henries (meaning the said knights) with mine own hand? 'Tis an evil hour for us that a third yet lives to be our victor."