San Antonio de Valero, one of five Spanish missions established by Franciscans in what is now San Antonio, is most commonly known as the site of the battle of the Alamo (1836). The mission was started by Father Antonio de San Buenaventura y Olivares, of the College of Santa Cruz of Querétaro, who first visited the region in 1709. In 1716 Olivares received approval from the Marqués de Valero, recently appointed viceroy of New Spain, for a plan to remove to San Antonio the dwindling mission of San Francisco Solano, founded in 1700 near the right bank of the Rio Grande at the site of present Guerrero, Coahuila. The viceroy also directed Martín de Alarcón, governor of Coahuila and Texas, to accompany Olivares with a military guard. After considerable delay, Olivares and Alarcón traveled separately to San Antonio in the spring of 1718. Mission San Antonio de Valero was founded on May 1 and followed four days later by the nearby San Antonio de Béxar Presidio and the civil settlement, Villa de Béxar. The mission, originally located west of San Pedro Springs, survived three moves and numerous setbacks during its early years. After a hurricane destroyed most of the existing buildings in 1724, the mission reached its latest site on the east bank of the San Antonio River. Hostile Apaches and allied tribes harassed the institution repeatedly during the 1730s and 1740s, and an epidemic of smallpox and measles devastated the resident Indian population in 1739. The mid-century decades witnessed the mission's most successful period. The Indian population climbed to 311 in 1745 and 328 in 1756, then declined. Throughout the mission's history, its Indian neophytes included members of more than a hundred groups, including Payaya, Pamaya, Pataguo, Tacame, Tamique, Xarame, Sana, Apache, Coco, Top, Karankawa, Ervipiame, and Yuta Indians. In 1773 the Franciscans of Querétaro transferred administration of San Antonio de Valero and its neighboring missions to the Franciscans of the College of Nuestra Señora de Guadalupe de Zacatecas. At the latter's request, the Spanish government in 1793 ordered San Antonio de Valero secularized. Its religious offices passed to the nearby diocesan parish of San Fernando de Béxar, while its lands, houses, seeds, tools, and draft animals were distributed among the remaining Indians, refugees from the East Texas settlement of Los Adaes, and local residents.
The mission's physical appearance altered according to its prosperity and population. The earliest buildings were of temporary construction and have not survived, but by 1727 work had begun on a stone convento, or priest's residence. The two-story, arcaded convento served as the friars' main building; it housed offices, kitchens, dining rooms, sleeping quarters, and guest rooms. A portion of this building survives as the Long Barracks Museum at the Alamo. The extant mission church, or Alamo Shrine, was begun during the 1750s, after the collapse of another begun in 1744. The ambitious design for the 1750s church featured a cruciform plan with sacristy, choir loft, barrel-vaulted roof, twin bell towers, a dome or cupola over the crossing, and an elaborately carved façade. As the mission's Indian population declined, however, work stalled, and the upper levels remained unfinished. Storerooms, a granary, workrooms, Indian residences, and an acequia, or irrigation ditch, completed the three-acre main compound. In addition to constructing buildings and irrigation ditches, Indians operated weaving, blacksmith, and carpentry shops; cultivated maize, beans, cotton, vegetables, and fruits in outlying fields and orchards; and on the mission ranch grazed livestock herds numbering hundreds of cattle, sheep, and goats, as well as horses and oxen.
Because the Spanish government failed to complete or adequately garrison the local presidio, the mission had frequently to provide for its own defense. Protective walls were erected, apparently after the massacre at Santa Cruz de San Sabá Mission in 1758; these walls, eight feet high by two feet thick, enclosed a main plaza located west of the convento and guarded by small artillery and a fortified gate. During the nineteenth-century struggle for political and military control of Texas, these rudimentary fortifications made the old mission symbolically and strategically important. The site served a variety of functions, including quarters for the Second Flying Company of San Carlos de Parras (1803-) and San Antonio's first hospital (1805 to 1812). Between 1810 and 1865 the former mission changed hands at least sixteen times, belonging variously to Spanish, Mexican, Texas, Union, and Confederate forces. Due to the combined effects of warfare, urban land development, and conflicting preservation goals, the grounds of the modern Alamo Shrine bear little resemblance to those of its eighteenth-century precursor. Much of the mission compound now lies buried beneath city streets and buildings and is revealed only occasionally and fragmentarily by archeological fieldwork. San Antonio de Valero lost its identity as an integrated complex during the nineteenth century. The United States Army occupied the site in 1846, provoking a three-way title controversy with the city of San Antonio and the Catholic Church. Although the church's claim prevailed in 1855, the mission chapel and convento both continued to be rented by the army and used as a supply depot until 1878. In addition to repairing the convento, army engineers directed the completion of the roofless mission church between 1850 and 1852, when they installed its distinctive arched gable. Private construction during the 1850s obliterated most of the old Indian houses and traces of the outer walls, which had been badly damaged during the Alamo battle. The mission's south gate, referred to as the "Low Barracks" in accounts of the Texas Revolution, served as a jail before being demolished in the late 1860s. The main mission plaza became a public park (now Alamo Plaza), while the grounds behind the convento disappeared beneath stables and shops.
Efforts to preserve the San Antonio de Valero site began during the 1880s. The state of Texas purchased the mission church from the Catholic Church in 1883 and conveyed the property to the city of San Antonio for a museum. The convento, acquired by a local merchant in 1877, served as a store until purchased by Clara Driscoll for the Daughters of the Republic of Texas in 1905. The Texas legislature subsequently approved state acquisition of the convento and simultaneously named the Daughters custodians of both it and the church. The ensuing controversy-often called the Second Battle for the Alamo-focused largely on whether the site should be restored as an eighteenth-century mission or a nineteenth-century battlefield. Adina de Zavala, granddaughter of Lorenzo de Zavala, the Mexican-born vice president of the Republic of Texas, proposed to emphasize the mission period and presented a two-story, arcaded convento as the principal structure. The Driscoll faction denied the convento's authenticity and supported a plan emphasizing the revolutionary period, with the church as the principal structure. Efforts by Governor Oscar B. Colquitt in favor of full-scale restoration of the convento failed in 1913, when opposition forces engineered the removal of the structure's second story; the remaining one-story walls remained roofless until refurbished as the Long Barracks Museum in the late 1960s. In 1966 the State Building Commission and the Witte Museum conducted archeological excavation on the mission grounds and uncovered foundations of adobe walls and numerous artifacts from both the Spanish colonial and Anglo-American occupations of the site. During the intervening years, the Daughters of the Republic of Texas acquired the entire city block behind the surviving mission structures and demolished later buildings to establish a memorial park. In the early 1990s controversy arose regarding proposed archeological digs around the area and the closing of Alamo Plaza to motorized traffic.