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On Friday, June 14, 1861, Union General Nathaniel Lyon captured the Missouri capital, Jefferson City, without a fight. Governor Claiborne Jackson and General Sterling Price fled south to Boonville, where the state militia were gathered. Jackson's administration was now a government-in-exile; Lyon had seized the machinery of the state government.
In a meeting earlier in the week that had been set up to attempt to bring some peace to Missouri, Lyon had declared war on the pro-Southern forces in the state led by Jackson and Price. The seizure of the capital was just the first step. He would, with barely a pause, move on to Boonville to battle the state militia forces there.