The poster for John Wayne's The Alamo (1960) celebrates its history with the line, "The Mission That Became a Fortress…The Fortress That Became A Shrine…," which is a concise and accurate summary of the story of the structure famously known as the Alamo in downtown San Antonio, Texas, USA.

Texas was claimed by Spain in the 16th century and began establishing mission complexes between 1680 and 1690. The purpose of these missions was to convert Native Americans to Catholicism, educate them according to the European concepts of history and civilization, and make them Spanish citizens. It was hoped that, in time, the indigenous converts would maintain the sites as self-sustaining communities.

In 1718, Martín de Alarcón, governor of Spanish Texas, founded the town of San Antonio de Béxar and, nearby, the Misión San Antonio de Valero, named in honor of San Antonio de Padua (St. Anthony of Padua) and the Marquess of Valero, the viceroy of New Spain. The first mission was a modest mud and straw structure destroyed by hurricanes in 1724. The site of the mission was then moved to the west bank of the San Antonio River (its present location), then outside the town.

The first buildings constructed at the new site were the priests' residence, then the barracks for the Native American converts, a textile workshop, and, finally, a chapel. The first chapel, begun in 1744, collapsed in 1756. The new chapel, begun in 1758, was originally planned as an ornate structure of three stories with bell towers and a dome (it would have looked like the San Fernando Cathedral in modern-day San Antonio), but only the first two stories were completed, and so the chapel never had a roof put on. This is the building most people recognize as the Alamo, discounting the Long Barracks, the only other original structure on the site today.

Greater effort went into enclosing the compound with a wall, and, eventually, the complex expanded to 3 acres (1.2 ha). The walls around the complex were strengthened against attacks by Apache and Comanche raiding parties. The self-sustaining missions had at first proven successful, but, as time went on, Native Americans left to establish their own homes or return to their people. The mission complexes became more of a financial burden than anything else by the 1790s, and, in 1793, the mission at San Antonio was secularized and abandoned.

Spanish Occupation

In 1803, the Second Flying Company of San Carlos de Parras (La Segunda Compañía Volante de San Carlos de Parras/Álamo de Parras), 100 Spanish lancers, arrived to fortify the mission. Spain had returned the Louisiana Territory to France in 1800, and France then sold that land to the USA in 1803 through the Louisiana Purchase. Spain feared a US invasion into Texas, and so the lancers were sent as a first line of defense, but also to protect Spanish citizens from Native American attacks and act as a police force in the region.

The mission would take its name either from the cottonwood trees nearby (Alamos), which came to be associated with these lancers (the most common theory), and/or from the company itself, whose name was shortened to La Compañía del Alamo or El Álamo. The El Alamo Company founded the first hospital in the region, serving both civilians and the military, in 1805. Between 1803 and 1809, the population of the mission grew, and quarters became cramped, so some people moved out and established a new community close by, La Villita, which still exists today.

Mexican Occupation

In 1809, with rumors of a US invasion swirling about, the El Alamo Company reinforced the existing walls of the mission and expanded the complex with new walls to the south, installing a large gate. This is how the mission first became a fortress. During the Mexican War of Independence (1810 to 1821), the El Alamo Company at first fought for Spain, but, in 1813, after surrendering to rebel forces, joined with them.

Most of the company left the Alamo, but some remained behind and were only reinforced in 1817. After Mexico won independence in 1821, more troops were sent to San Antonio de Béxar to protect the northern border of Mexico from US invasion and illegal immigration. In 1832, the garrison at the Alamo was reinforced, and, in 1835, when Mexican General Martín Perfecto de Cos arrived with his army, the El Alamo Company joined them.

When the Texas Revolution (1835 to 1836) broke out, the El Alamo Company fought alongside Cos' men during the Siege of Béxar from October through December 1835. Cos made further improvements to the complex, including a ramp in the chapel, which supported three cannon at the top, strengthening the walls, and construction of a palisade to close the gap in the south wall. Outnumbered and running low on provisions and ammunition, Cos surrendered the Alamo to the Texians and left the fort on 11 December 1835, and the El Alamo Company went with them.

Texian/Tejano Occupation

After the Texians and Tejanos took the Alamo, Colonel James C. Neill's company of 100 volunteers garrisoned the fort. Neill sent requests for reinforcements, but the provisional government of Texas was in no position to recruit men, and, besides, many who had fought in the battles since October 1835 believed the war was over when Cos surrendered and so had gone back to their homes and farms.

Neill was certain the Mexican Army would return, however, and so he and engineer Green B. Jameson set about repairing damage done to the complex during the Siege of Béxar, strengthening the walls, and installing catwalks. General Sam Houston agreed with Neill that the Mexican Army was coming back, but he did not believe the Alamo could be held and so sent James "Jim" Bowie to remove the artillery (Cos had left 19 cannons behind as well as small arms and ammunition) and blow up the fort.

Bowie and Neill both felt the Alamo should be fortified and defended. Colonel Juan N. Seguín, commanding the Tejano Company, agreed. Bowie was unable to remove the artillery anyway because he did not have enough oxen to pull the cannon, so the choice came down to leaving 19 cannons for the Mexican Army to reuse or fortify and hold the Alamo. In February 1836, Lt. Colonel William Barret Travis arrived with 3ö men of the regular army, and, soon after, Davy Crockett of Tennessee with more volunteers. Colonel Neill left to deal with family matters, and Travis took over his command.

In February 1836, General Antonio López de Santa Anna, President of Mexico, arrived with his army, vastly outnumbering the defenders of the Alamo, and laid siege to the complex for 13 days, 23 February to 6 March. Early on the morning of the 6th, Santa Anna launched his assault, storming the Alamo and massacring the defenders. Those who surrendered were executed immediately after the battle. Among those who fell defending the Alamo were former members of El Alamo Company, who were part of Seguín's command.

Later Use

The bodies of all the garrison of the Alamo were burned on pyres – except that of José Gregorio Esparza, whose brother, Francisco, was with Santa Anna's army and requested he be allowed to give Gregorio a proper burial – and the fort was then garrisoned by Mexican troops under General Juan Andrade. Andrade repaired damage done to the complex during the siege and battle and held the fort until after Santa Anna was defeated at the Battle of San Jacinto on 21 April 1836.

San Jacinto was the decisive battle of the Texas Revolution, and the defeated Mexican forces had to leave the region. Andrade ordered the Alamo burned before leaving in May, tearing down walls and spiking the cannon. The Alamo was left in ruins, but the battle of 6 March 1836 had quickly become legendary, and the site was soon a tourist attraction. Visitors carried off pieces of the walls and chapel as souvenirs, and local vendors quickly seized on the opportunity, gathering debris from the site and selling it to tourists.

By 1840, the San Antonio Town Council also recognized the profit that could be made from the ruin and began charging people $5.00/wagonload for any stone they wanted to repurpose in their own projects. This is how the low barracks, where Jim Bowie was killed, disappeared.

The fort was occupied by US troops during the Mexican-American War of 1846 to 1848, and significant repairs were made. After the war, repairs to the Alamo continued under the US Quartermaster, and it was at this time that the famous bell-shaped parapet was added to the top of the chapel. This is also when the chapel was given the first roof it had ever had.

During the American Civil War (1861 to 1865), the Alamo served as a fort of the Confederate Army until 1865 when they were defeated, and it was again garrisoned by Union troops. The complex continued as a working fortress from 1865 to 1876, when the garrison moved to Fort Sam Houston and the Alamo was abandoned.

The Catholic Church still technically owned the site and, in 1877, sold the building known as the Long Barracks to the businessman Honoré Grenet, who turned it into a general store, museum, and tourist attraction. After Grenet died in 1882, the building was sold in 1883 to Hugo, Schmeltzer & Company, a grocery, who built a second story on the long barracks and turned it into a general store. The chapel became a warehouse.

In 1883, the Catholic Church sold the chapel to the State of Texas for $20,000.00, and the state government was now responsible for its upkeep. Nothing was done, however, and so a local schoolteacher, Adina De Zavala, stepped in to spearhead restoration and preservation efforts. De Zavala was a member of The Daughters of the Republic of Texas (DRT), established in 1892, and she brokered a deal with Gustav Schmeltzer to give her group the first option to buy the low barracks.

In 1903, Schmeltzer offered the building to the DRT for $75,000.00, but they did not have the money. Heiress Clara Driscoll became involved, however, donating the money. Driscoll had very definite ideas about what should be done with the buildings, and these conflicted with those of De Zavala. De Zavala wanted the site returned to how it looked in 1836, while Driscoll wanted the long barracks torn down and a park established around the chapel. The two women refused all compromise, and eventually Driscoll formed her own DRT, claiming it was the legitimate steward of the site, while De Zavala made the same claim for her group.

The conflict between the two groups, which eventually involved the state government, is known as the Second Battle of the Alamo. In 1910, Governor Oscar B. Colquitt resolved the matter by removing both groups as stewards of the site and returning care of the Alamo to the state. The Hugo, Schmeltzer & Company additions to the long barracks were torn down, and this building and the chapel were preserved. Through Driscoll's efforts, stewardship was returned to the DRT, and, although the site now conformed to what De Zavala had argued for, she was expelled from the group.

The Alamo was already considered a shrine to fallen heroes by 1936 when, for the Texas Centennial, the state government commissioned the Alamo Cenotaph from local sculptor Pompeo Coppini, dedicated on 11 November 1940. The Alamo was designated a National Historic Landmark in 1960, it was listed on the National Register of Historic Places in 1966, and the long barracks became a museum in 1968.

In 2015, the Alamo became a UNESCO World Heritage site. Today, it is operated by the non-profit company Alamo Trust and is visited by millions of people from around the world every year. Along with the famous San Antonio River Walk nearby, the mission that became a fortress that became a shrine is today the most popular tourist attraction in Texas.