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 (now San Antonio).

About one hundred Texians had been garrisoned at the mission, and they were supplemented by around one 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. On the basis of "perhaps" ten sources, William C. Davis posits three separate escapes of Texian combatants from the Alamo, consisting of perhaps 80 men.Davis, William C. (1998). Three Roads to Alamo. New York: HarperCollins World, pp. 562; 736-37, n. 105. Phillip Thomas Tucker also sees three discrete Texian escapes, totaling as many as 120 men.Tucker, Phillip Thomas. (2010). Exodus from the Alamo: the anatomy of the last stand myth. Havertown, Pa: Casemate, pp. 261, 287-98, 302. Nearly all Texian combatants were killed. Those who fled outside the walls were dispatched by Mexican lancers, who had been positioned for that purpose.

Several noncombatants were sent to Gonzales to spread word of the Texian defeat. The news sparked a scramble 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 portion of the Mexican Army led by Santa Anna at the Battle of San Jacinto, on April 21, 1836. The capture of Santa Anna ended the war.

Hardin notes that the Texians "could scarcely believe that enemy troops, the majority of whom had never known defeat in Texas, would complacently obey the orders of a captured commander."Hardin (1994: 245). The cessation of hostilities and the withdrawal to Mexico of the divided forces, led by other Mexican generals, guaranteed the survival of the Republic of Texas.

In Mexico, the battle has often been overshadowed by events from the Mexican–American War of 1846–1848. The Alamo complex gradually became known as a battle site rather than a former mission. The Texas Legislature purchased land and the long barracks building (the former convento) in the early part of the 20th century. The Alamo church, which had been purchased by the state in 1883, was designated an official Texas State Shrine. A roofless ruin at the time of the battle, it was intended to have three floors and a large dome framed by two tall bell towers. The gable and the pitched roof it concealed were added by the U.S. Army in 1849.

The Alamo has been the subject of numerous non-fiction works, the first of which were produced in 1843. Most Americans, however, are more familiar with the myths and legends spread by many of the movie and television adaptations,Nofi (1992), p. 213. including the 1950s Disney miniseries Davy Crockett and John Wayne's 1960 film The Alamo.

Background

In 1835, following the repeal of the federalist 1824 Constitution of Mexico, Mexico adopted Las Siete Leyes ("The Seven Laws"), a new constitutional framework that replaced the First Mexican Republic with a unitary republic officially named the Mexican Republic ().Felipe Tena Ramírez, Leyes fundamentales de México, 1808–1971. pp. 202–248.

New policies that entailed restricting or eliminating slavery, limiting immigration from the U.S., and increased enforcement of laws and import tariffs (tariffs had initially been waived for seven years) incited many immigrants to revolt.Todish et al. (1998), p. 6. The border region of Mexican Texas was largely populated by immigrants from the United States, some legal but most illegal. Mexico tried to end Anglo American immigration in 1830, but their number doubled by 1834, from 10,000 to 21,000).Torget, (2015: 150-57). Some immigrants had brought large numbers of slaves with them, so that by 1836, there were approximately 5,000 enslaved persons in a total non-native population estimated at 38,470. Campbell, author of the first book-length study of slavery in Texas in 1989, says slavery was minimized within Texas by "many historians, writers, and creators of popular culture" who "preferred to see Texas as essentially western rather than southern."Campbell, Randolph B. (1989). An Empire for Slavery: The Peculiar Institution in Texas, 1821-1865. Baton Rouge: Louisiana State University Press, p. 1. The Handbook of Texas lacked an entry on slavery, and what Campbell calls the "best state history" devoted less than three pages to it.Campbell (1989), p. 4. Campbell notes that in the 1850s more than a quarter of free Texas families owned slaves, and the latter constituted 30% of the state's population, percentages comparable to that of Virginia, "the oldest slave state in the Union."Campbell (1989), p. 2.

The colonists were accustomed to a federalist government that made special exemptions from Mexican law exclusively for them, and to extensive individual rights, including the right to own slaves. Mexico's shift towards centralism and its interest in enforcing its laws resulted in growing displeasure among the colonists,Henson (1982), p. 96. particularly when the centralized government ended local federal exemptions to the ban on slavery, previously negotiated by Stephen Austin and others. Already suspicious after previous United States attempts to purchase Texas, Mexican authorities blamed much of the Texian unrest on United States immigrants. Most of them had entered illegally and made little effort to adapt to the Mexican culture, and they continued the practice of slavery in violation of Mexico laws.Barr (1990), p. 4.

In October, Texians engaged Mexican troops in the first official battle of the Texas Revolution. Determined to quell the rebellion of immigrants, Santa Anna began assembling a large force, the Army of Operations in Texas, to restore order. Most of his soldiers were less-experienced recruits, many conscripted.Todish et al. (1998), p. 20.

The Texians defeated the Mexican troops already stationed in Texas. The last group of Mexican soldiers in the region—commanded by Santa Anna's brother-in-law, General Martín Perfecto de Cos—surrendered on December 9 following the siege of Béxar.Barr (1990), p. 56. By this point, the Texian Army was dominated by very recent arrivals to the region, primarily illegal immigrants from the United States.

Gary Brown says the Texian armies that fought at San Antonio and Goliad were dominated by mercenaries. He characterizes the most effective of these militias that were raised outside of Texas: "Santa Anna claimed the New Orleans Greys were mercenaries and pirates, and technically he was correct.... they were military mercenaries, not pioneers or settlers, and they came to Texas for adventure and material gain—not constitutional freedoms."Brown, Gary. (1999). Volunteers in the Texas Revolution: The New Orleans Greys. Simon and Schuster, pp. 284-85.

Many of the Texian settlers who had participated in the revolt returned home, unprepared for a long campaign. Mexico's response to this violation of its sovereign rights was the Tornel Decree, a "no quarter" policy formulated by the Mexican Minister of War. Approved by the Mexican congress and issued on December 30, 1835, it defined irregular invaders as pirates, "being citizens of no nation presently at war with the republic, and fighting under no recognized flag."Winders, (2017: 424). In this historical period, captured pirates were executed immediately.Barr (1990), p. 63.Scott (2000), p. 71.

Josefina Zoraida Vázquez characterizes the decree "a desperate attempt to maintain control of the territory in the face of the flagrant intervention of foreigners against Mexico's government."Vázquez, Josefina Zoraida. (1997). “The Colonization and Loss of Texas: A Mexican Perspective,” in Jaime E. Rodríguez and Kathryn Vincent, eds. Myths, Misdeeds, and Misunderstandings: the Roots of Conflict in U.S.-Mexican Relations. Wilmington: SR Books, p. 74. Santa Anna reiterated this message in a strongly worded letter to United States President Andrew Jackson. This letter was not widely distributed, making it likely that most of the United States recruits serving in the Texian Army were not aware there would be no prisoners of war.Scott (2000), pp. 74–75.

When Mexican troops departed San Antonio de Béxar (now San Antonio, Texas, USA), Texian soldiers captured the Mexican garrison at the Alamo Mission which was a former Spanish religious outpost which had been converted to a makeshift fort by the recently expelled Mexican Army. Described by Santa Anna as an "irregular fortification hardly worthy of the name", the Alamo had been designed to withstand an assault by Indigenous attackers, not an artillery-equipped army.

The complex was sprawled over , providing almost of perimeter to defend. An interior plaza was bordered on the east by the church and to the south by a one-story building known as the Low Barracks. A wooden palisade stretched between these two buildings.Todish et al. (1998), p. 10. The two-story Long Barracks extended north from the church.Myers (1948), p. 181. At the northern corner of the east wall stood a cattle pen and horse corral. The walls surrounding the complex were at least thick and ranged from high.Myers (1948), p. 180.The plaza covered an area long and wide. The Low Barracks was long, and the Long Barracks was long and wide. (Myers (1948), pp. 180–181.)

To compensate for the lack of firing ports, Texian engineer Green B. Jameson constructed catwalks to allow defenders to fire over the walls; this method, however, left the rifleman's upper body exposed. Mexican forces had left behind 19 cannons, which Jameson installed along the walls. A large 18-pounder had arrived in Texas with the New Orleans Greys. Jameson positioned this cannon in the southwest corner of the compound. He boasted to Texian Army commander Sam Houston that the Texians could "whip 10 to 1 with our artillery".

Prelude to battle

The fact remains that the Texian garrison was undermanned and underprovisioned, with fewer than 100 soldiers remaining by January 6, 1836.Todish et al. (1998), p. 29. Colonel James C. Neill, the acting Alamo commander, wrote to the provisional government: "If there has ever been a dollar here I have no knowledge of it". Neill requested additional troops and supplies, stressing that the garrison was likely to be unable to withstand a siege lasting longer than four days.Todish et al. (1998), p. 30. The Texian government at that time was in turmoil and unable to provide much assistance.Todish et al. (1998), p. 31.A week after Neill sent his letter, the Texian provisional legislature impeached the governor, who in turn disbanded the legislature. The interim constitution had given neither party the authority to take these actions, and no one in Texas was entirely sure who was in charge. (Todish et al. (1998), pp. 30–31.) Four different men claimed to have been given command over the entire army.Sam Houston, James Fannin, Frank W. Johnson, and Dr. James Grant. (Todish et al. (1998), p. 30.) On January 14, Neill approached one of these men, Sam Houston, for assistance in gathering supplies, clothing, and ammunition.