The Alamo began its existence in 1718 as Mission San Antonio de Valero, the oldest of San Antonio's five Spanish mission. In 1724, Spanish officials relocated Valero to the spot that the Alamo now occupies. Two original building remain from the mission period (1724-1793)-the church, or modem Shrine, and the convento, or Long Barrack. The mission was desecularized in 1793. Around 1803, a Spanish cavalry unit called the Second Flying Company of San Carlos de Parras, was quartered in the former mission compound and the site began several decades of use by the military, first Spanish followed by Mexican, Texan, United States, Confederate, and then U.S. again. The Alamo is best remembered for the epic battle which occurred in 1836 as one of the key events of the Texas Revolution. In 1847, the U.S. Army rented the Alamo from the Catholic Archdiocese and converted the Long Barrack into offices and storerooms, doing the same to the church in 1850. When the army moved to Government Hill (Fort Sam Houston) in 1876, the site underwent a period of commercial development. The State of Texas acquired the church in 1883 but the Long Barrack remained in private hands until 1905 when the State Legislature finally authorized its purchase. The site expanded in the 1930s with the acquisition of several acres east of the Shrine and the construction of the Alamo Sales Museum and Arcade as well as the conversion of Fire Station No. 2 into Alamo Hall. In 1950, the Daughters of the Republic of Texas Library opened on the grounds. In 1968, the Long Barrack Museum was opened in conjunction with HemisFair: its current permanent exhibit was installed in 1985. In 1997, a permanent outdoor exhibit known as the Wall of History was installed that depicts the Alamo's 300 year-long historic past. The Alamo is managed and operated by the Daughters of the Republic of Texas, who were granted custodianship of the site by the State Legislature in 1905 in recognition for their efforts to keep the Long Barrack out of the hands of commercial developers so it could be preserved as a historic site. According to Texas Law, the DRT must preserve the Alamo as a sacred memorial to the heroes who immolated themselves upon that hallowed ground. The DRT receives no monetary help from local, state, or federal government, depending solely on money from donations and proceeds from the gift shop to preserve the complex and maintain exhibits.