Following Mississippi's secession, Governor John J. Pettus ordered militia units to Vicksburg to prevent the Mississippi River being used to attack the state or reinforce federal garrisons. On this evening, the regularly-scheduled Cincinnati to New Orleans riverboat A.O. Tyler, under Captain John Collier, had shots fired across her bows off Vicksburg and was forced to halt for inspection before being allowed to continue her journey. When war began, this vessel became the U.S.S. Tyler, and on August 13, 1861 fired its own shots into Vicksburg. (By John Osborne)