It was a very hot summer’s day, with a burning sun. Warren was suffering from a nervous headache, and threw himself on a bed; but, after the alarm was given, he rose, and, saying that his headache was gone, started for the scene of action. It is said that one of his students, Dr. [David] Townsend, accompanied him a part of the way on foot, but that, a short distance from the College [Harvard], Warren was on horseback. He overtook two friends [James Swan and James Winthrop] who were walking to the battle-field, and, exchanging with them the usual salutations, he passed along towards Charlestown. . . .This has become the standard account of Warren’s death, particularly the headache. Frothingham relied on a variety of sources available to him in 1865: contemporaneous documents like a letter from Col. Prescott and an orderly book, early histories such as the Rev. William Gordon’s from 1788 (which said, “general Warren was shot in the back part of his head, on the right side: having mechanically clapt his hand to the wound, he dropt down dead”) and Gen. Heath’s memoir, and recollections from Gen. Putnam’s and Col. Prescott’s sons.
Warren went to the rail-fence: here he was on foot. He met General [Israel] Putnam, who, it is said, offered to receive orders from Warren, who replied, “I am here only as a volunteer. I know nothing of your dispositions; nor will I interfere with them. Tell me where I can be most useful.”
Putnam directed him to the redoubt, with the remark, “There you will be covered;” when Warren said, “Don't think I came to seek a place of safety, but tell me where the onset will be most furious?” General Putnam again named the redoubt.
Warren then went forward to Breed’s Hill, and into the redoubt. There was a feeling at this time, in the ranks at this post, so manifest was the peril, that, through the oversight, presumption, or treachery of the officers, the men would be all slain. They needed encouragement. Warren was enthusiastically received; “all the men huzzaed.” He said that he came to encourage a good cause, and that a re-enforcement of two thousand men was on its way to their support.
Colonel [William] Prescott asked the general if he had any orders to give. Warren replied that he had none, and exercised no command, saying, “The command is yours.” This is the relation by General [William] Heath. Judge Prescott, who heard the fact from his father, the colonel, is more circumstantial in relating the incident. “General Warren,” Judge Prescott says, “came to the redoubt, a short tune before the action commenced, with a musket in his hand. Colonel Prescott went to him, and proposed that he should take the command; observing that he (Prescott) understood he (Warren) had been appointed a major-general, a day or two before, by the Provincial Congress. General Warren replied, “I shall take no command here. I have not yet received my commission. I came as a volunteer, with my musket, to serve under you, and shall be happy to learn from a soldier of your experience.”
Warren undoubtedly served as a volunteer in the battle that began soon after he arrived. . . . On such a field, Warren fought a good fight. He was applied to for orders, and gave them. . . . As the regulars, showing “a forest of bayonets,” came over one side of the redoubt, the militia fell back to the other side, and there was a brief but fierce hand-to-hand struggle, when the butts of the muskets were used; and Warren was now seen for the last time by Colonel Prescott, who was not among those who ran out of the redoubt, “but stepped long, with his sword up,” as he parried the thrusts that were made at his person. So great was the dust arising now from the dry, loose soil, that the outlet was hardly visible. Warren was among the last to go out.
Just outside of it, there was much mingling of the British and Provincials, and great confusion, when the firing for a few moments was checked. At this time, Warren endeavored to rally the militia, a contemporary account says, “sword in hand.” He was recognized by a British officer, who wrested a musket out of a soldier’s hand, and shot him. He fell about sixty yards from the redoubt, being struck by a bullet in the back part of his head, on the right side. Having mechanically clapped his hand to the wound, he dropped down dead. The retreating and the pursuing throng passed on by his body.
However, for the crucial detail that a “British officer” shot a sword-wielding Warren with a soldier’s musket, Frothingham’s source was an unpublished manuscript by Samuel Adams Wells, which seems unreliable. It’s also unclear where Frothingham found his information about Warren’s walk to the battlefield. He apparently didn’t have access to the Rev. Dr. Jeremy Belknap’s notes on Warren’s last day, quoted here; they weren’t published until ten years after this biography.