On the failure of the rising the law was rendered more rigorous. Magistrates were directed to arrest all Lollards and hand them over to the bishops; a conviction of heresy was made to entail forfeiture of blood and of estate; and thirty-nine prominent Lollards were brought to execution. Cobham escaped, and for four years longer strove to rouse revolt after revolt. He was at last captured on the Welsh border and burned as a heretic.

With the death of Oldcastle the political activity of Lollardry came suddenly to an end, while the steady persecution of the bishops, if it failed to extinguish it as a religious movement, succeeded in destroying the vigour and energy which it had shown at the outset of its career. But the House of Lancaster had, as yet, only partially accomplished the aims with which it mounted the throne. In the eyes of the nobles, one of Richard's crimes had been his policy of peace, and the aid which they gave to the revolution sprang partly from their hope of a renewal of the war. The energy of the war-party was seconded by the temper of the nation at large, already forgetful of the sufferings of the past struggle and longing only to wipe out its shame. The internal calamities of France offered at this moment a tempting opportunity for aggression. Its King, Charles the Sixth, was a maniac, while its princes and nobles were divided into two great parties, the one headed by the Duke of Burgundy and bearing his name, the other by the Duke of Orleans and bearing the title of Armagnacs. The struggle had been jealously watched by Henry the Fourth, but his attempt to feed it by pushing an English force into France at once united the combatants.

Their strife, however, recommenced more bitterly than ever when the claim of the French crown by Henry the Fifth on his accession declared his purpose of renewing the war. No claim could have been more utterly baseless, for the Parliamentary title by which the House of Lancaster held England could give it no right over France, and the strict law of hereditary succession which Edward asserted could be pleaded, if pleaded at all, only by the House of Mortimer. Not only the claim, indeed, but the very nature of the war itself was wholly different from that of Edward the Third. Edward had been forced into the struggle against his will by the ceaseless attacks of France, and his claim of the crown was a mere afterthought to secure the alliance of Flanders. The war of Henry, on the other hand, though in form a renewal of the earlier struggle on the expiration of the truce made by Richard the Second, was in fact a wanton aggression on the part of a nation tempted by the helplessness of its opponent and galled by the memory of former defeat. Its one excuse indeed lay in the attacks which France for the past fifteen years had directed against the Lancastrian throne, its encouragement of every enemy without and of every traitor within.

In the summer of 1415 the King sailed for the Norman coast, and his first exploit was the capture of Harfleur. Dysentery made havoc in his ranks during the siege, and it was with a mere handful of men that he resolved to insult the enemy by a daring march, like that of Edward, upon Calais. The discord, however, on which he probably reckoned for security, vanished before the actual appearance of the invaders in the heart of France; and when his weary and half-starved force succeeded in crossing the Somme, it found sixty thousand Frenchmen encamped on the field of Agincourt right across its line of march. Their position, flanked on either side by woods, but with a front so narrow that the dense masses were drawn up thirty men deep, was strong for purposes of defence but ill suited for attack; and the French leaders, warned by the experience of Crécy and Poitiers, resolved to await the English advance. Henry, on the other hand, had no choice between attack and unconditional surrender. His troops were starving, and the way to Calais lay across the French army. But the King's courage rose with the peril. A knight in his train wished that the thousands of stout warriors lying idle that night in England had been standing in his ranks.

Henry answered with a burst of scorn. "I would not have a single man more," he replied. "If God give us the victory, it will be plain that we owe it to His grace. If not, the fewer we are, the less loss for England." Starving and sick as were the handful of men whom he led, they shared the spirit of their leader. As the chill rainy night passed away, his archers bared their arms and breasts to give fair play to "the crooked stick and the grey goose wing," but for which - as the rime ran - " England were but a fling," and with a great shout sprang forward to the attack. The sight of their advance roused the fiery pride of the French; the wise resolve of their leaders was forgotten, and the dense mass of men-at-arms plunged heavily forward through miry ground on the English front. But at the first sign of movement Henry had halted his line, and fixing in the ground the sharpened stakes with which each man was furnished, his archers poured their fatal arrow flights into the hostile ranks. The carnage was terrible, but the desperate charges of the French knighthood at last drove the English archers to the neighbouring woods, from which they were still able to pour their shot into the enemy's flanks, while Henry, with the men-at-arms around him, flung himself on the French line.

In the terrible struggle which followed the King bore off the palm of bravery: he was felled once by a blow from a French mace, and the crown on his helmet was cleft by the sword of the Duke of Alençon; but the enemy was at last broken, and the defeat of the main body of the French was followed at once by the rout of their reserve. The triumph was more complete, as the odds were even greater, than at Crécy. Eleven thousand Frenchmen lay dead on the field, and more than a hundred princes and great lords were among the fallen.