Missouri's loyalties were divided at the outset of the Civil War. In June 1861, Union Brig. Gen. Nathaniel Lyon attacked a secessionist concentration in St. Louis and forced approximately 4,000 belligerents, including governor Claiborne Jackson, to evacuate the city. Union Col. Franz Sigel quickly organized an expedition into southwest Missouri with orders to fully disperse the group, led by Governor Jackson. Sigel camped with approximately 1,000 loyal Missouri infantry and artillerymen in the vicinity of Carthage, near the Arkansas border, on July 4th. The next morning, Jackson and his poorly armed militiamen, who nonetheless greatly outnumbered Sigel, revealed themselves on a ridge north of the town, compelling Sigel to either attack or withdraw. After a sustained artillery bombardment, Sigel launched an attack. While his men were heavily engaged, Sigel received word that a large Confederate force—actually unarmed recruits—was moving towards his flank. Sigel ordered a withdrawal into the town. The Confederate pursuit climaxed with a firefight in the town square, where Jackson's men were ultimately unable to dislodge or destroy Sigel's force before the Union men retreated that evening. The battle sustained Confederate hopes for the loyalties of the state and paved the way for battle with Lyon's forces at Wilson's Creek a month later.