This rare ambrotype is believed to depict the surrender of the U.S. Arsenal and federal forces under the command of General Twiggs' to the Confederates forces commanded by brigadier general Ben McCulloch in the main plaza in San Antonio, Texas.

U.S. General David Twiggs, a Georgian, was sympathetic to the secessionist cause and attempted to avoid bloodshed. He was dismissed from federal service after the surrender of San Antonio and joined the Confederate army, but age and infirmity took his life early in the war.

Ben McCulloch, a legendary Texas Ranger and Indian fighter, had come to Texas as a youth with David Crockett. In the 1850s he served as a U.S. marshal in East Texas and on a successful peace commission to Brigham Young's Mormons in Utah. Jefferson Davis appointed McCulloch the second-ranking brigadier general in the Confederate Army. In charge of Indian Territory, McCulloch would be killed at Pea Ridge in March 1862.