The Battle of the Alamo (February 23 – March 6, 1836) 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 (modern-day San Antonio, Texas, United States). About one hundred Texians, wanting to defy Mexican law and maintain the institution of chattel slavery in their portion of Coahuila y Tejas by seeking secession from Mexico, were garrisoned at the mission at the time, with around a hundred subsequent reinforcements led by eventual Alamo co-commanders James Bowie and William B. Travis. On February 23, approximately 1,500 Mexicans marched into San Antonio de Béxar as the first step in a campaign to retake Texas. In the early morning hours of March 6, the Mexican Army advanced on the Alamo. After repelling two attacks, the Texians were unable to fend off a third attack. As Mexican soldiers scaled the walls, most of the Texian fighters withdrew into interior buildings. Those who were unable to reach these points were slain by the Mexican cavalry as they attempted to escape. Almost all of the Texian inhabitants were killed.
Several noncombatants were sent to Gonzales to spread word of the Texian defeat. The news sparked both a strong rush to join the Texian army and a panic, known as "The Runaway Scrape", in which the Texian army, most settlers, and the government of the new, self-proclaimed but officially unrecognized Republic of Texas fled eastward toward the U.S. ahead of the advancing Mexican Army. Santa Anna's execution of surrendering soldiers during the battle inspired many Texians and Tejanos to join the Texian Army. 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.
Within Mexico, the battle has often been overshadowed by events from the Mexican–American War of 1846–1848. In 19th-century Texas, the Alamo complex gradually became known as a battle site rather than a former mission. The Texas Legislature purchased the land and buildings in the early part of the 20th century and designated the Alamo chapel as an official Texas State Shrine.
The Alamo has been the subject of numerous non-fiction works beginning in 1843. Most Americans, however, are more familiar with the myths and legends spread by many of the movie and television adaptations, including the 1950s Disney miniseries Davy Crockett and John Wayne's 1960 film The Alamo.