this wall was added as the original wall took in much more area across Houston Street to where the Federal Building is at. How Old Are The Two Original Buildings? Construction of the Convento (or Long Barrack) began in 1724, shortly after the mission was relocated to this site. Records indicate it was completed in 1744. That makes it more than 250 years old. The Long Barrack has undergone several renovations and reconstructions. In 1847 the U.S. Army repaired the structure: drawings from that period show it with two full stories. By 1876 the military had relocated their facilities to what would become Fort Sam Houston. During the 1870s and 1880s, merchants used the Long Barrack as a store. A wooden framework constructed to resemble a fort covered much of the Long Barrack. The wooden framework and the second story were stripped away in 1913 in an effort to remove the "unoriginal" portions of the building, leaving only the walls standing. The walls were repaired and roofed in 1968, as part of the renovations to the Alamo for HemisFair, creating the Long Barrack Museum. http://www.thealamo.org/education/fun-facts.html#1