In another part of the battlefield, Henry notes that they seem to be winning ("Well have we done, thrice valiant countrymen"), and he asks about his kinsman, the Duke of York, whom he saw fighting and covered with blood. Exeter repeats York's last words and tells him in a moving speech how bravely York died. The Duke of York, wounded and dying, stumbled upon his noble cousin, the Earl of Suffolk, who lay dying. York took his cousin "by the beard, kissed the gashes," and called upon Suffolk to tarry for a moment so they could die together. Then:
So did he turn and over Suffolk's neck
He threw his wounded arm and kiss'd his lips;
And so espoused to death, with blood he seal'd
A testament of noble-ending love. (24-27)
Exeter tells how he wept like a woman at the sight, and King Henry is about to join "with mistful eyes" when, hearing an alarm, he realizes that the French have reinforced their armies, and he orders his men to kill all of the French prisoners.
First, this scene functions to announce the beginning of the English successes. Then it shifts its emphasis to narrate the deaths of the Duke of York, who has played only a small role in the drama, and the death of the Earl of Suffolk, who has not even appeared in the drama. This might seem confusing to the modern viewer, but from our knowledge of many of Shakespeare's history plays, some of the greatest moments are associated with a description of love and death; added to this is the bloody gore of the battlefield. Thus, in order to give a depth to the deaths of two who have played virtually no role in the development of the drama, this scene must be rendered within the context of a grim battle atmosphere.
Shakespeare's main purpose, here, is to show another aspect of Henry the King — one who can mourn and weep for his kinsmen and fellow soldiers fallen in battle, and then, in the next moment, put aside all sense of personal loss and sternly command the deaths of all the French prisoners in order to ensure the safety of the English soldiers. This quality of decisiveness is the stuff that all great field commanders are made of (at least Shakespeare seems to be saying this). We see evidence of the complete presence of mind and control that Henry has in the midst of a raging battle and in the throes of passion because of the deaths of his kinsmen.
For many modern readers, Henry's command to kill all the French prisoners might seem extremely cruel and barbaric or savage, but unless Henry wants to be defeated and have all of his men put to death, he must execute the prisoners before they are freed or before they revolt. In terms of historical accuracy, Henry did not reportedly issue this order until he discovered that the French had massacred all of the young boys and lackeys left in charge of the English equipment in the camp. This massacre is covered in the next scene.