annexed to the United States in 1845, and this annexation led to a war between the United States and Mexico. The war began in 1845 and ended in 1848, the result being highly favorable to the armies of the former country and proportionally disastrous to those of the latter.
Hostilities did not actually begin until March, 1846, when General Zachary Taylor's army crossed the Nueces and marched in the direction of the Rio Grande. Mexico denied that Texas extended to the Rio Grande, and persisted in regarding the Nueces as the boundary. When, therefore, General Taylor crossed the latter river the movement was considered by the Mexicans an act of war, and they made immediate preparations for resisting the advance of the enemy. Taylor's advance was a series of almost uninterrupted successes, and in the early part of 1847 Northern Mexico lay at his feet. The American flag floated over the fortress of Monterey, and the Mexican army, four times the strength of its opponents, had been defeated at Buena Vista. To complete the conquest it was necessary to move upon the capital, a work which was intrusted to General Winfield Scott, the commander-in-chief of the armies of the United States.
On the 6th of March, 1847, the army destined for the advance to the city of Mexico was concentrated near Vera Cruz. It comprised the then standing army of the United States—four regiments of artillery, eight of infantry, one of mounted riflemen, and detachments of dragoons, besides eight volunteer regiments of infantry and one of cavalry. General Scott commanded in person, with Generals Worth, Twiggs, and Patterson as his brigadiers. Under the last named were Generals Quitman, Pillow, and Shields, who were destined to make their names known before the end of the campaign. The first step in advancing upon the city of Mexico was to capture Vera Cruz, which was defended by the fortress of San Juan d'Uloa, a fortress built on a reef in front of the city
