P. G. T. Beauregard
David Bullock Harris was appointed a captain of engineers in the Virginia militia on May 2, 1861. By July, he was serving on the staff of Confederate Army Brigadier General Philip St. George Cocke. He was engaged at the First Battle of Bull Run on July 21, 1861. Thereafter, Harris was assigned to the staff of General P. G. T. Beauregard.