Frank Crawford Armstrong

Francis Crawford Armstrong (November 22, 1835 – September 8, 1909) was a United States Army cavalry officer and later a brigadier general in the Confederate States Army during the American Civil War. He is also known for being the only Confederate general to fight on both sides during the Civil War. His father, Francis Wells Armstrong, died three months before his son's birth. In 1854, Armstrong's mother married Mexican–American War general Persifor Smith.

Civil War service In June 1861, Armstrong was promoted to captain in the regular army. In July, he led a company of Union cavalry at the First Battle of Bull Run. He married Maria Polk Walker, daughter of Col. Joseph Knox Walker. Col. Walker is the brother of Lucius Marshall Walker, who also served as a Confederate general.