Thus fell the two main keys of the valley, and thus did all the divisions of the American army at length reach the open and comparatively unobstructed plains of the valley.
Worth soon reunited his division on the main straight road to the capital, and was joined by General Pillow, who, advancing from Coyoacan to attack the rear of San Antonio, as we have already related, soon perceived that the hacienda had fallen, and immediately turned to the left, through a broken country of swamps and ditches, in order to share in the attack on Churubusco. And here, it was felt on all sides, that the last stand must be made by Mexico in front of her capital.
The hamlet or scattered houses of Churubusco, formed a strong military position on the borders of the stream which crosses the highway, and, besides the fortified and massive convent of San Pablo, it was guarded by a tête de pont with regular bastions and curtains at the head of a bridge over which the road passes from the hacienda of San Antonio to the city. The stream was a defence;—the nature of the adjacent country was a defence;—and here the fragments of the Mexican army,—cavalry, artillery and infantry, had been collected from every quarter,—panic stricken, it is true,—yet apparently resolved to contest the passage of the last outwork of importance in front of the garita of San Antonio Abad.
When Worth and Pillow reached this point, Twiggs had already been sometime hotly engaged in attacking the embattled convent. The two advancing Generals immediately began to manœuvre closely upon the tête de pont, which was about four hundred and fifty yards east of the convent, where Twiggs still earnestly plied the enemy. Various brigades and regiments under Cadwallader, Lieutenant Colonel Smith, Garland, Clark, Major White and Lieutenant Colonel Scott continued to press onward towards the tête de pont, until by gradual encroachments under a tremendous fire, they attained a position which enabled them to assault and carry the formidable work by the bayonet. But the convent still held out. Twenty minutes after the tête de pont had been taken, and after a desperate battle of two hours and a half, that stronghold threw out the white flag. Yet it is probable that even then the conflict would not have ended, had not the 3d infantry under Captains Alexander, J. M. Smith, and Lieutenant O. L. Shepherd, cleared the way by fire and the bayonet to enter the work.
Whilst this gallant task was being performed in front of the Mexican defences, Generals Pierce and Shields had been engaged on our left, in turning the enemy's works so as to prevent the escape of the garrisons, and to oppose the extension of numerous corps from the rear, upon and around our left. By a winding march of a mile around to the right, this division under the command of Shields, found itself on the edge of an open, wet meadow, near the main road to the capital, in the presence of nearly four thousand of the enemy's infantry, a little in the rear of Churubusco. Shields posted his right at a strong edifice, and extended his left wing parallel to the road, to outflank the enemy towards the capital. But the Mexicans extended their right more rapidly, and were supported by several regiments of cavalry, on better ground. Shields, accordingly, concentrated his division about a hamlet, and attacked in front. The battle was long and bravely sustained with varied success, but finally resulted in crowning with victory the zeal and courage of the American commander and his gallant troops. Shields took 380 prisoners, including officers; while at Churubusco seven field pieces, some ammunition, one standard, three Generals, and 1261 prisoners, including other officers, were the fruits of the sharply contested victory.
This was the last conquest on that day of conquests. As soon as the tête de pont fell, Worth's and Pillow's divisions rushed onward by the highway towards the city, which now rose in full sight before them, at the distance of four miles. Bounding onward, flushed and exultant, they encountered Shields' division, now also victorious, and all combined in the headlong pursuit of the flying foe. At length the columns parted, and a small part of Harney's cavalry, led by Captain Kearney of the 1st dragoons, dashed to the front and charged the retreating Mexicans up to the very gates of the city.
Thus terminated the first series of American victories in the valley of Mexico.
Note.—It is ungracious to criticize unfavorably the conduct of a conquered foe, but there are some things in Santa Anna's behavior at Contreras and Churubusco, which must not be passed silently. At Contreras, he came with aid, by a short and fine highway, to the field at a late period, when the Americans, moving slowly over an unknown and broken country, had already outflanked with a strong force, Valencia's left, and he then made no effort whatever, with his large support, to relieve the beleagured general. If he did not design doing any thing, why did he come at all; and, if as he says, he believed Valencia could, during the night, withdraw all his forces, after spiking his guns, by a secret path of which he apprised him, why did he not take the same path to aid him? Did he believe that it was best to lose Valencia and his division only, without risking the loss of the large support under his own command? In the morning of the 20th it was certainly too late for action, but Santa Anna must have been convinced, when he ordered the retreat from the Hacienda of San Antonio, and thus voluntarily opened a gate for Worth's advance, that now, if ever, had arrived the moment for a general action in front of the city, the key of which, on the main road, was the convent of Churubusco and the adjacent works. The loss of Valencia's army and materiel was undoubtedly disheartening, but, according to his own account, Santa Anna had been prepared for an event which he foresaw. This should not have destroyed his self-possession if he sincerely desired victory. When Contreras fell, he had, in reality, only lost a division consisting of five or six thousand men. The whole centre and left wing of his army were untouched, and these must have numbered at least 20,000. Yet, if we admit the brave resistance of the garrison, only hastily thrown into the convent and works at Churubusco, it may then be asked what masterly effort Santa Anna made (at the moment when he had actually drawn the American army into the valley) to bring on a general action with all the fresh troops either under his own command or under that of obedient, brave, skilful, and patriotic officers? The Mexican accounts of these actions, and in fact, his own despatch from Tehuacan, dated 19th Nov. 1847, exhibit no able manœuvres on the last field with which he was perfectly and personally familiar. The Americans stormed a single point,—and the battle was over, though bravely fought by those who were under cover and by the traitor battalion of San Patricio, formed of renegades from our army. The despatches of Santa Anna, like most of the Mexican despatches after military or political disaster, seem rather designed to criminate others, and to throw the whole blame of ultimate complete defeat on Valencia, than to point out the causes of conquest in spite of able generalship after the fall of Contreras. See Santa Anna's despatches, Mexico 23 Aug. 1847; and Tehuacan, 19 Nov. 1847, in Pillow's Court Martial, pp. 532 and 540. See also Apuntes para la historia de la guerra, &c., &c., chapters XVII-XVIII-XIX, and Ripley's History of the War, vol. 2, p. 256; "No part of the Mexican force was ready for battle, except Rincon's command," says this writer.