He marched to Leith without opposition, but the castle of Edinburgh was in the hands of David, Duke of Rothesay, the king's eldest son, who sent Henry a contemptuous defiance, offering to do battle with him, with one, two, or three hundred Scottish knights against the same number of English. Henry received the proposal with an equal affectation of contempt, and waited some days for the approach of an army under the Duke of Albany. But he waited in vain, for that astute nobleman took care not to engage a force which famine was fast defeating for him. Provisions became unattainable, and Henry was compelled to retreat to the borders.
The expedition was far from equalling the prestige of those of his predecessors, especially the first and third Edwards, but at the same time it must be allowed that it exceeded them in humanity. Whether the real motive were humanity or policy, it was in effect both. His protection was instantly afforded to all who sought it, and the royal banner displayed from tower or steeple was a signal that no violence or plunder of the inhabitants was permitted. Thus he mitigated the terrors of war, and set an example of moderation to both friend and enemy, such as had hitherto been unknown in European warfare.
Henry was hastily recalled from the borders of Scotland by a formidable revolt in Wales. There a new enemy, and a most troublesome one, had been needlessly provoked by the injustice of a nobleman, Lord Grey de Ruthin. Lord Grey, who had large estates in the marshes of Wales, appropriated a part of the demesne of a Welsh gentleman, Owen ap Griffith Vaughan, commonly called Owen Glendower, or Owen of Glendowerdy. In his youth Owen had studied the law in the inns of court; was called to the bar, but afterwards became an esquire to the Earl of Arundel; and then, during the campaign in Ireland, to Richard II., to whom he was much attached. When Richard was deposed Owen retired to his paternal estate in Wales, where the aggression of Lord Grey took place. Lord Grey was closely connected with the new king; Owen was an adherent of the old one; and this probably encouraged Lord Grey to attempt the injustice. But Owen Vaughan was possessed of the high spirit and quick blood of the Welsh. He disdained to submit to this arrogant oppressor. He petitioned the king in Parliament for redress, but met with the fate which was only too probable from a poor partisan of the fallen king in opposition to the powerful one of the reigning dynasty. Though his cause was ably pleaded by the Bishop of St. Asaph, his petition was rejected, and Owen, who boasted that he was descended from Llewelyn, the last of the ancient Princes of Wales, boldly took his cause into his own hands, and drove Lord Grey by force of arms from his lands. The indignant nobleman appealed to Henry, who embraced his cause, and issued a proclamation at Northampton on the 19th of September, 1400, commanding all men of the nine neighbouring counties to repair instantly to his standard, to march into Wales, and reduce Glendower, who was declared a rebel. The fiery patriot, burning with indignation at this gross injustice, the very day that the news of it reached him, rushed forth, burnt Lord Grey's town of Ruthin, declared himself Prince of Wales, and called on his countrymen to follow him and assert the liberty of their country. The spark was thrown into the magazine of combustible material of which Wales was full, for it was crushed but not contented. The people flocked from all quarters to Owen's standard. They admitted his claims to the princedom of the country without much inquiry, for they saw in him a companion and a deliverer from the English yoke. Owen's superior education in London inspired them with profound respect, and hence their opinion that he was a potent magician, possessing dominion over the elements. Henry marched against him, but Owen retired into the mountains, and the king was compelled to return.
In the next year Henry marched once more against the Welsh, who continued to assemble in still greater bodies under the banner of Owen Glendower, and make inroads into England, plundering and killing wherever they came. Twice in this year Henry took the field against them, but on his approach they retired into their mountains and eluded his pursuit. As regularly as he returned, they again rushed down into the champaign country, and in one of these incursions in Pembrokeshire, Owen gained a considerable victory, thus raising his reputation and augmenting his force.
Wearied by these fruitless attempts to subdue the insurgent Welsh, Henry returned towards the end of the year to London, but found as little repose or satisfaction there. Secret enemies were around him, treason dogged his steps into his very chamber, and he came near to losing his life by means of a sharp instrument of steel, having three long points, which was concealed in his bed.
Meantime the revolt of Owen Glendower had been acquiring strength. Not only did the Welsh, amid their native mountains, flock to his standard, but such of them as were in England left their various employments and hastened back to join in the great efforts for the independence of their country. Not only labourers and artisans, but the apprentices in London and other cities caught the contagion, and went streaming back. The students left the universities, and the Commons at length presented themselves before the king, representing to him how all these various classes of men were hastening to Wales laden with armour, arrows, bows, and swords. Owen took the field early, engaged his original adversary, Lord Grey, defeated and made him prisoner on the banks of the Vurnway. Sir Edmund Mortimer, uncle to the young Earl of March, collected all the friends and vassals of the family to prevent the devastation of their lands. They mustered 12,000, with whom they attacked Glendower near Knighton, in Radnorshire, but were defeated, and Sir Edmund was made prisoner, with a loss of 1,100 of his men. At the same time the young earl himself, who had been allowed by Henry to retire to his castle of Wigmore, though a mere boy, took the field, but was also captured by Glendower, and carried into the mountains.
Henry, who had the strongest reasons for wishing the Mortimers out of his way, we may suppose was by no means displeased at their seizure by Glendower; and this was sufficiently evident, for he refused to allow the Earl of Northumberland, who was closely allied to the Mortimers, to treat for their ransom with Glendower. Still, Henry put forth all his vigour to reduce the Welsh chieftain. He entered Wales at three different points; his son, the Prince of Wales, leading one division of the army, the Earl of Arundel the second, and himself the third. The Prince of Wales pushed into the heart of the mountains with a bravery which was the herald of Agincourt. He reached the very estate of Glendower and burnt down his house, and laid waste his property; but Glendower kept aloof on the hills till he saw young Henry retire, when he poured down like one of his native torrents, and carried desolation in his rear. The English armies found it impossible to come to close quarters with these enemies, and equally impossible to procure provisions. The weather was insupportable. The rains descended in incessant deluges, the tempest tore away the king's tent, and everything appeared to confirm the ideas of the people, and indeed of contemporary historians, that Owen Glendower, by the power of necromancy, could "call spirits from the vasty deep," and bring the elements in league against his foes. Henry was compelled to return baffled from the contest.
The news which reached the king from Scotland was equally extraordinary. It was that King Richard was alive and residing at the Scottish court, and about to invade England at the head of a large army. The king issued repeated proclamations against the propagation of these rumours, and it was now that he put to death Sir Roger Clarendon, the natural son of the Black Prince, nine Franciscan friars, and several other persons, for disseminating this account.
Border warfare was begun on a large scale by Henry's supporters the Percies, and the Scottish nobles retaliated. On one of these occasions, the command being in the hands of Sir Patrick Hepburn of Hailes, the Scots broke into England and laid waste the country with great fury; but going too far, they were intercepted by Percy and the Earl of March, a Scottish refugee, and no connection of Mortimer's, on Nesbit Moor in the Merse. The Scots were only 400 in number, but they were well armed and mounted, and consisted of the flower of the Lothians. The battle was long doubtful, but March, who had not arrived before, coming up with 200 men from the garrison at Berwick, decided the fortune of the day. Hepburn himself was killed, and such was the destruction of his best knights and his followers that the spot still retains the name of Slaughter Hill.
Henry was delighted with the news of this victory. He complimented the Percies and March on their prompt bravery, and commanded them to call out and assemble the feudal levies of the northern counties, as the Scots were menacing the borders on the west, and ravaging the neighbourhood of Carlisle. Henry's information was correct. To revenge the defeat of Nesbit Moor, Lord Archibald Douglas took the field with 10,000 picked men, and the Earl of Albany, who now wielded unlimited power in Scotland, sent his son Murdoch, Earl of Fife, to join him with a strong body of archers and spearmen. The most distinguished knights and barons of Scotland followed the Douglas banner. A nobler army for its numbers never left Scotland under a Douglas. But the present Earl of Douglas was as noted for his lack of caution, and for his numerous consequent defeats, as his ancestors had been for their care and success, so that he had acquired the by-name of "the tine-man," the losing man. He rushed on across the Tweed with his accustomed impetuosity, and never stayed his course till he arrived before the gates of Newcastle. Everywhere the country people, unsupported by any armed force, had fled before him, and he and his followers now found themselves so loaded with booty that it was necessary to return.