State Historian Bill O'Neal introduces the battle of the Alamo, considered an iconic call to arms in the Texas Revolution and a shrine to Texas liberty. O'Neal describes how a small presidio mission established in 1718 by Franciscan missionaries in San Antonio became a source of Texas martyrdom and pride. O'Neal also introduces some of the main figures who played an important role, including Antonio Lopez de Santa Anna, William Barrett Travis, Martin Perfecto de Cos, James Bowie, and others. Video courtesy of Texas Talks and the Texas State Historical Association.