In the spring of 1861 Captain Nathaniel Lyon allegedly slipped through a Missouri militia camp disguised as an old blind woman in a bonnet. Missouri was a slaveholding border state whose governor, Claiborne Fox Jackson, preached armed neutrality while secretly working with Richmond. Lyon surrounded the militia at Camp Jackson, marched the prisoners through St. Louis, and the shooting that followed killed 28 civilians. At the Planters House Hotel on June 11, Lyon ended talks with Jackson and Sterling Price by declaring, This means war, then chased the Missouri State Guard into the southwest corner of the state.

By August Lyon held Springfield with about 5,400 men after expiring 90-day enlistments drained his ranks, facing more than 12,000 under Ben McCulloch and Price. He gambled on a dawn attack on August 10 and split his force with Franz Sigel. A gray-uniformed Louisiana regiment overran Sigel’s guns because Union officers mistook it for the 1st Iowa. Lyon was shot through the heart leading a counterattack, the first Union general killed in combat, and Missouri was left with two rival governments and years of guerrilla war.

• A rainstorm on August 9 led McCulloch to cancel his own attack and pull in his pickets, leaving the camp blind.
• An acoustic shadow bent the sound of the opening cannon fire over McCulloch’s headquarters, and he first took it for a false alarm.
• Union gunner James Totten dueled across the valley with Confederate captain William Woodruff, his former artillery student.
• Judge James McBride’s Ozark militia, led by country lawyers, stumbled into a flanking position against the 1st Missouri.
• The 1st Kansas suffered one of the highest casualty rates of any Union regiment in the war in a single morning.