A signal mortar shell was fired from Fort Johnson over Fort Sumter. Firing from surrounding batteries soon followed, starting the battle. A Virginia secessionist, Edmund Ruffin, claimed to have fired the "first shot" of the battle and the Civil War.
At about 7 a.m., some two and a half hours after the general bombardment of the fort had commenced, Anderson gave the order for Sumter's guns to begin their reply. The first shot was fired by his second-in-command, Captain Abner Doubleday.
Bibliography: OR, pp. 18, 305; Chesnut, Mary Chesnut's Civil War, pp. 45-51;Thomas, Confederate Nation, p. 92; Current, Lincoln and the First Shot, p. 161.