It was now determined by General Scott to resume the bombardment early next morning, and to attack with the columns under Quitman and Pillow. In aid of this a storming party was detailed from Worth's division of ten officers and two hundred and sixty men, under command of Captain Samuel McKenzie, Second Artillery, and a like detail from Twiggs's division under Captain Silas Casey, Second Infantry, in support of Pillow's movement, and General P.F. Smith's brigade of Twiggs's division was ordered to the support of Quitman. The bombardment was renewed early on the morning of the 13th. Four companies of the voltigeur regiment, under Lieutenant-Colonel Joseph E. Johnston, were instructed, on the cessation of firing, to move rapidly under cover of the wall and enter the inclosure at its opening. Four companies under Colonel Timothy P. Andrews were ordered to unite with Johnston, deploy as skirmishers, and drive the enemy from his shelter. McKenzie was ordered to move in the rear of Johnston, with orders to follow the latter through the breach and advance rapidly and carry the main work by assault. A force of men carrying scaling ladders were placed with Johnston. Colonel William Trousdale, with the Eleventh and Fourteenth Regiments, and one section of Magruder's battery, under command of Lieutenant Thomas Jonathan Jackson, was placed in position in the road leading on the left of Chapultepec to the city, and ordered to advance and prevent an advance of the enemy in that direction. General Cadwallader was directed by General Pillow to execute the orders. General Smith's brigade had orders to move on the right of the column of attack and cut off the retreat of the enemy in that direction. General Scott now notified the commanding officers of the attacking forces to be ready to move when the signal was given. The troops moved forward promptly at the signal, and after a brave and desperate struggle its gallant defender, General Bravo, surrendered. With the exception of Riley's brigade, Steptoe's battery, and the garrison at Mexcoac, all of the American army were engaged. General Scott's forces engaged amounted to about seven thousand five hundred men. The Mexican authorities state that eight hundred men were in Chapultepec. The brigades of Rangel and Peña were stationed near. The Mexicans engaged did not probably exceed four thousand men.
Among the prisoners captured were Generals Monterde, Saldana, and Norriega, the former superintendent of the military school, and forty of his pupils. On the commencement of the engagement these youths deserted their schoolrooms, and, arming themselves, joined in the defense of Chapultepec and fought with great bravery.
Preparations were now made for an advance and the capture of the capital. The pursuit of the retreating enemy was followed on two roads leading to the city, and there was considerable desultory fighting. At 1 o'clock A.M. on the 14th a deputation of citizens arrived at General Worth's headquarters, who were sent by him, under charge of Major William W. Mackall, to General Scott's headquarters. They reported that General Santa Anna had fled from the city, leaving it with the civil authorities, and they came to ask favorable terms of surrender. General Scott declined to make any terms with them, telling them that the city had practically been in his possession from the day before; that he would levy a moderate tax, and would be governed by no terms except his own and such only as the honor and dignity of the United States would require. Early on the morning of the 14th a white flag was displayed at the Garita de Belen, and General Quitman was requested to take possession, as the city had been evacuated by the Mexican army. Leaving a guard at the Belen gate, General Quitman marched his command and took possession of the citadel. Leaving the Second Pennsylvania Regiment at the citadel, he marched to the Grand Plaza, followed by Steptoe's battery. The Marine Battalion was placed in the National Palace, and the American flag was hoisted from its summit. Lieutenant G.T. Beauregard was dispatched to notify General Scott. About eight o'clock the general in chief, accompanied by his staff, with an escort of cavalry, all in full dress, passed through the northwestern angle into the Grand Plaza. The line of soldiers presented arms, lowered colors, and gave the drum beat. General Scott uncovered in acknowledgment of the salute, dismounted, and passed into the porte-cochère of the palace, followed by Generals Quitman and Smith and officers of the staff. He said, "Gentlemen, we must not be too elated with our success." Then turning, he said: "Let me present to you the Civil and Military Governor of the City of Mexico, Major-General John A. Quitman. I appoint him at this instant. He has earned the distinction, and he shall have it." The general then ascended the stairway and at once wrote General Order No. 284, as follows:
"Headquarters of the Army,
"Mexico, September 14, 1847.
"1. Under the favor of God, the valor of this army, after many glorious victories, has hoisted the colors of our country in the capital of Mexico and on the palace of its Government.
"2. But the war is not yet ended. The Mexican army and Government have fled, only to watch an opportunity to turn upon us with vengeance. We must, then, be upon our guard.
"3. Companies and regiments will be kept together, and all stand on the alert. Our safety is in military discipline.
"4. Let there be no drunkenness, no disorders, no straggling. Stragglers will be in great danger of assassination, and marauders shall be punished by courts-martial.