At the outbreak of war, supposedly neutral Missouri was a soup of intrigue. The flashpoint was the ‘Camp Jackson Massacre’ (10 May) in St Louis, when the the Union commander of the city’s arsenal, General Lyon, opened fire on a mob trying to free paramilitaries he had arrested for plotting the arsenal’s seizure. Lyon moved swiftly west, routing the State Guard and expelling the state legislature led by the secessionist Governor Claiborne Jackson. Jackson went on to defeat a separate Union force at Carthage (5 July), while Lyon teamed up with reinforcements sent from Leavenworth. Meanwhile Missouri’s militias had united with Confederate army reinforcements under General McCulloch. The combined forces then clashed at Wilson’s Creek (August 10), with the Confederates victorious. The Missouri militias then proceeded to capture Lexington (20 September) using sodden hemp bales to absorb Union fire during their assault. A final Union attack near Cairo was repulsed (7 November).