The Siege of Bexar
Between October and early December 1835, an army of Texian volunteers laid siege to a Mexican army in San Antonio de Bexar. The Mexican General Santa Anna knew of the growing resistance against him in Texas, and so he set his brother-in-law General Martin Perfecto de Cos to San Antonio de Bexar and 600 men to quell the rebellion.
In October 1835, a group of Texians volunteered to serve under Stephen F. Austin and Edward Burleson and lay siege to San Antonio de Bexar. Before dawn on December 5th of that same year, James Neill distracted the Mexican forces with artillery fire on the Alamo. At this same time, Ben Milam and Francis W. Johnson led two divisions in a surprise attack on the city.
After four days of fighting, Cos sought to consolidate his troops at the Alamo, but a large part of his cavalry decided not to continue fighting and deserted. Mexican General Cos surrendered that same day, December 9, 1835. Cos promised to return to Mexico.
When the fighting ended, Texas has between 30 and 35 casualties, while Mexican losses totaled about 150; the difference reflected the greater accuracy of the Texans' rifles. Most of the Texas volunteers went home after the battle, but Texas troops remained in town, which left San Antonio and all of Texas under the Texans' control.
This battle was one of the first significant campaigns of the Texas Revolution. Within a few weeks, Texas would declare independence from Mexico. However, after the Mexican Army was defeated, in 1835 Santa Anna was intent on recapturing the mission. In February 1836, he returned to San Antonio de Bexar with several thousand soldiers. This led to the famous Battle of the Alamo where the Texians held out for 13 days before the Alamo fell on March 6, 1836. The Mexican Army killed and/or executed all the 189 defenders.
On April 21, General Sam Houston faced off with the numerically superior army of Santa Anna and defeated it, leading to Texas independence from Mexico. Texas remained a country for nine years before joining the United States.
And that's just the way it is.