The speech that Shakespeare attributes to Henry V at Agincourt comes from dialogue that was recorded in the Gesta Henrici Quinti, a chronicle of the early years of Henry's reign. In the Gesta, the night before Agincourt, Sir Walter Hungerford wished for ten thousand more archers from England. Henry reprimanded him for this wish, because "these I have here with me are God's people whom He deigns to let me have at this time." The Henry V of the Gesta never fails to credit the Almighty for his victories.

There are some sources which say that Henry gave an oration on the day of the battle. Some of these are more elaborate than others, but the general thrust of all of them is Henry encouraging his men and, in one source, telling them that he would rather fight to the death than be taken for ransom. He may also have said something to his captains before the English advance later in the day. Sir Thomas Erpingham then threw his baton in the air and shouted "Now strike!" to signal the raising of banners and the general advance. Amusingly, French chroniclers present seem to have had trouble understanding Erpingham (who would have spoken English to his men); they recorded "now strike" as a single nonsense word in French.

Whatever the actual content of Henry's speech (if indeed he gave one), the real Henry V would never have suggested that common soldiers become his brothers. He did dub some men-at-arms into knights following the battle, but he certainly would not have extended this to the entire army. Henry V was notoriously prickly about his status and his royal prerogatives. The threats of treason and rebellion constantly hung over him and disloyalty was punished swiftly and harshly. While he valued his soldiers, he also was careful to maintain order and discipline. He was not afraid to hang them if they violated his orders.