The Battle of the Alamo was a pivotal event and military engagement in the Texas Revolution. Following a 13-day siege, Mexican troops under President General Antonio López de Santa Anna reclaimed the Alamo Mission near San Antonio de Béxar, killing most of the occupants. Santa Anna's refusal to take prisoners during the battle inspired many Texians and Tejanos to join the Texian Army. Motivated by a desire for revenge, as well as their written desire to preserve a border open to immigration and the importation and practice of slavery, the Texians defeated the Mexican Army at the Battle of San Jacinto, on April 21, 1836, ending the conquering of the Mexican state of Coahuila y Tejas by the newly formed Republic of Texas.

The Texas Revolution was a rebellion of colonists from the United States and Tejanos against the centralist government of Mexico in the Mexican state of Coahuila y Tejas. Although the uprising was part of a larger one, the Mexican Federalist War, that included other provinces opposed to the regime of President Antonio López de Santa Anna, the Mexican government believed the United States had instigated the Texas insurrection with the goal of annexation. The Mexican Congress passed the Tornel Decree, declaring that any foreigners fighting against Mexican troops "will be deemed pirates and dealt with as such, being citizens of no nation presently at war with the Republic and fighting under no recognized flag". Only the province of Texas succeeded in breaking with Mexico, establishing the Republic of Texas. It was eventually annexed by the United States.