Awakes, a pro-Union paramilitary organization that he intended to arm with the arsenal's supplies and muster into the ranks of the federal army. Upon obtaining command of the arsenal, Lyon armed the Wide Awake units under guise of night. Lyon had most of the weapons in the arsenal secretly moved across the river to Illinois, and on May 10, he led the 2nd Infantry to the camp, forcing its surrender. Riots broke out in St. Louis after Lyon marched his prisoners through the city. The event provoked the Camp Jackson Affair of May 10, 1861, in which Lyons' troops opened fire on a crowd of civilians, killing 28 and injuring at least 90. The Camp Jackson Affair polarized the population of Missouri, leading many once-neutral citizens to advocate secession and setting the stage for sustained violence between the opposing factions. St. Louis Riot The division of loyalties between Union and Confederacy resulted in further loss of life on May 11, 1861. Union soldiers of the Fifth Regiment, United States Reserve Corps, Missouri Volunteers were attacked by Confederate sympathizers within hours of being mustered into service. The regiment was marching from the federal arsenal when it was attacked on the corner of Walnut and Broadway. Shots were exchanged, and six persons were killed. The Fifth Regiment consisted primarily of loyal Germans, having been recruited from the city's Tenth Ward. Civil War During the Civil War, St. Louis stayed under Union control because of the strong military base and public support from loyal Germans. The largest percentage of volunteers served in the Union army, though many also went south to fight for the Confederacy. Some people who stayed in the city during the war and supported the South smuggled supplies, medicine, and otherwise assisted Confederate soldiers. No major battles were fought in or near the city, but the Mississippi River was a vital highway during the war. Divided loyalties to the Union and Confederacy caused rifts in some families in St. Louis. This divide remained consistent throughout the entirety of the war. Though many believed in the cause of abolition, others were concerned about the economic response and potential destruction of critical infrastructure in the blossoming city. Benton Barracks was a Union Army military encampment established during the war at the present site of the St. Louis Fairground Park. After the Battle of Lexington, the Post and Convalescent Hospitals were added to