Over the next decade, Thornton's business boomed: he served as clerk to the mayor and board of aldermen and was county representative to the state temperance society. He also served as secretary of the board of trustees of the Guadalupe Male and Female College. Thornton's letters home attracted other family members and friends to the area. In 1853 his brother Harvey visited the area to take photographs and tour the area; however, after a few letters home, he was never heard from again. The Brackenridges became interested in the area and moved to join their Thornton cousins: James Thornton had married the sister of John A. Brackenridge's wife, uniting the two families. From this beginning, the Brackenridges would grow to become powerful bankers, builders, landowners, feminists, and philanthropists in the
San Antonio, Texas, and
Austin, Texas, communities. During the
American Civil War, however, the Thornton family was pro-Union, which created local hostility. For safety, the family moved to Minnesota to wait out the war. After his brother, Henry Harrison Thornton, was killed at the
Battle of Stones River, Thornton decided to enlist in the Union Army and, with his connections, received an appointment to the Quartermaster Corps and was named commissary of the brigade, serving under General
Nathaniel P. Banks. While on his way to the
Siege of Vicksburg, Thornton became ill and was forced to return to
Minnesota to recuperate. After the war, for health reasons, his doctors advised that he return to Texas. ==Military reconstruction==