From the Gesta Henrici Quinti (The Exploits of Henry V), Translated by F Taylor & J.S. Roskel (1975)
"And on the following day, namely Friday on the Feast of St Crispin and Crispinian, 25 October, as dawn rose, the French positioned themselves in ranks, squadrons and wedges, and took their place in front of us on the field named Agincourt, across which was our route to Calais, and they were of a most terrifying number. Cohorts of cavalry stood in many hundreds on both sides of their vanguard in order to burst through our battle line and our force of archers. And that vanguard of soldiers on foot consisted of all the choicest noblemen: it was a forest of lances and a grave multitude of gleaming shields and cavalry at their sides, and was approximately thirty times greater than ours. But their rearguard and wings, squadrons and wedges were all on horseback, as if prepared for flight rather an to remain in place, and in respect to ours they were of an incomparable number."
"When the time came near for the enemy’s offensive, the French cavalry that had been positioned on the sides made attacks against our archers who were on either side of our army. But soon, as God willed, they were compelled to retreat amidst the showers of arrows, and to flee to the rearguard, with the exception of a very small number of men who ran amidst the archers and the groves, not without slaughter and wounding; and indeed, with the exception of the many men whom stakes driven into the ground and the barrage of missiles aimed at both horses and knights held back from fleeing far away. Whereas the enemy missiles which were aimed at the rear of the armed men and on their sides, after the first but hasty movement, harmed very few people, they retreated at the strength of our bows."
"Then a most bitter battle raged, and our archers notched the ends of their arrows and sent them against their flanks, continually renewing battle. When their arrows had been used up, they took up axes, stakes, swords and the heads of lances that lay between them, and laid the enemy low, ruining and transfixing them. For the almighty and merciful God, who is always miraculous in His work, and who wanted to show his mercy to us, whom it pleased that the crown of England, which has long been invincible, to remain under the power of our gracious king, His soldier, and his small retinue, as soon as the battle lines had been joined together and the battle begun, increased our power that the shortage of our provisions had previously debilitated and weakened, removed the terror from them, and gave them a fearless heart. And it seemed to our elders that the English had never attacked their enemy more bravely, intrepidly or wilfully."
And, military expedient or not, certainly the most tragic part of the battle:
"But then at once, for what wrath of God it is unknown, a shout arose that the rearguard of the enemy’s cavalry was of an incomparable number and fresh, and that they had restored their position and battle line in order to overcome us in our small numbers and weary state. And the prisoners were killed at once, without any heed to the difference between people, excepting the dukes of Orleans and Bourbon and other illustrious men who were in the king’s battle line, along with a very few others, by the swords of either their captors or others that followed them, lest they should be ruinous to us in the ensuing battle. But after a short while, the enemy ranks, according to the will of God once they had tasted the bitterness of our weapons and our king had drawn close to them, abandoned to us a field of blood along with carriages and their draughthorses, many being filled with provisions, weapons, lances and bows. And thus when, on God’s orders, the strength of that people had been dissipated and the rigours of the war had finished, we who had obtained victory returned through the masses, mounds and piles of dead men, and saw and inspected them, but not without the pain and tears of many, because so many outstanding and most powerful soldiers – had only God been with them – had sought their own deaths in such a manner from us, completely against our wishes, and had thus vainly destroyed and broken up the glory and honour of their own dwelling place. And if that was a site for compunction and piety in us as strangers passing by, how much more lamentation and wailing did it cause for the local people, who were watching and seeing the militia of their country being destroyed and despoiled in this manner! And I truly believe that there is not a heart of flesh or even one of stone that, if it had seen and considered the terrible deaths and bitter wounds of so many Christians, would not have broken itself and dissolved into tears out of grief. Indeed, however illustrious or respectable they were, the men, having been despoiled earlier by our English pillagers, did not have on our retreat any more covering, except only to cover their nature, than that which nature had woven for them on first entering the light."