At daylight, accordingly, Valencia’s intrenched camp was assaulted. General Pierce was soon in the saddle at the head of his brigade, which retained its position in front, thus serving to attract the enemy’s attention, and divert him from the true point of attack. The camp was stormed in the rear by the American troops, led on by Riley, Cadwallader, and Dimmick; and in the short space of seventeen minutes it had fallen into the hands of the assailants, together with a multitude of prisoners. The remnant of the routed enemy fled towards Churubusco. As Pierce led his brigade in pursuit, crossing the battle-field, and passing through the works that had just been stormed, he found the road and adjacent fields everywhere strewn with the dead and dying. The pursuit was continued until one o’clock, when the foremost of the Americans arrived in front of the strong Mexican positions at Churubusco and San Antonio, where Santa Alma’s army had been compelled to make a stand, and where the great conflict of the day commenced.
General Santa Anna entertained the design of withdrawing his forces towards the city. In order to intercept this movement, Pierce’s brigade, with other troops, was ordered to pursue a route by which the enemy could be attacked in the rear. Colonel Noah E. Smith (a patriotic American, long resident in Mexico, whose local and topographical knowledge proved eminently serviceable) had offered to point out the road, and was sent to summon General Pierce to the presence of the commander-in-chief. When he met Pierce, near Coyacan, at the head of his brigade, the heavy fire of the batteries had commenced. “He was exceedingly thin,” writes Colonel Smith, “worn down by the fatigue and pain of the day and night before, and then evidently suffering severely. Still there was a glow in his eye, as the cannon boomed, that showed within him a spirit ready for the conflict.” He rode up to General Scott, who was at this time sitting on horseback beneath a tree, near the church of Coyacan, issuing orders to different individuals of his staff. Our account of this interview is chiefly taken from the narrative of Colonel Smith, corroborated by other testimony.
The commander-in-chief had already heard of the accident that befell Pierce the day before; and as the latter approached, General Scott could not but notice the marks of pain and physical exhaustion against which only the sturdiest constancy of will could have enabled him to bear up. “Pierce, my dear fellow,” said he,--and that epithet of familiar kindness and friendship, upon the battle-field, was the highest of military commendation from such a man,--“you are badly injured; you are not fit to be in your saddle.” “Yes, general, I am,” replied Pierce, “in a case like this.” “You cannot touch your foot to the stirrup,” said Scott. “One of them I can,” answered Pierce. The general looked again at Pierce’s almost disabled figure, and seemed on the point of taking his irrevocable resolution. “You are rash, General Pierce,” said he; “we shall lose you, and we cannot spare you. It is my duty to order you back to St. Augustine.” “For God’s sake, general,” exclaimed Pierce, “don’t say that! This is the last great battle, and I must lead my brigade!” The commander-in-chief made no further remonstrance, but gave the order for Pierce to advance with his brigade.