In October 1864, Confederate Major General Sterling Price entered Jackson County with about 12,000 troopers, around 500 wagons loaded with plunder and war supplies, and roughly 3,000 volunteers who had joined him across Missouri, and he needed to get these wagons and recruits safely back to Arkansas. Opposing him was an army under Major General Samuel R. Curtis of about 3,000 veteran cavalrymen and 16,000 newly mustered Kansas State Militia, while a cavalry division of about 3,500 under Major General Alfred Pleasonton pursued Price from behind. Over three days, these one Confederate and two Union armies fought across 35 square miles, and by 2:00 p.m. on Sunday, October 23, the Confederates were defeated and retreating south, after which the two Union forces joined in pursuit the next day. One of Price's aims in invading Missouri in the fall of 1864 had been to disrupt the November elections, but 16 days after the defeat at Westport, Missouri overwhelmingly elected a Republican governor and delegates to a state convention that would consider emancipation, and 80 days after the Confederate defeat the Missouri State Convention abolished slavery in Missouri, with Governor Thomas C. Fletcher issuing an Ordinance Abolishing Slavery in Missouri on January 11, 1865, 20 days before Congress passed the Thirteenth Amendment, which was ratified in December 1865 and abolished slavery nationwide. The campaign also included the first combat service during the American Civil War by an African American unit officered by an African American: after U.S. Secretary of War Edwin M. Stanton authorized Curtis on June 30, 1864, to raise an artillery battery of African Americans with African Americans as officers, Curtis ordered Major Robert H. Hunt on July 2 to recruit, organize, and train such a battery, Hunt appointed William D. Matthews and Patrick H. Minor as recruiting officers, and on October 16 Hunt ordered the Independent Battery, U.S. Colored Light Artillery into service against Price's Confederates; one section under 2d Lieutenant Patrick H. Minor, with two 10-pounder Parrott rifles, moved to the front and fought on October 22 and 23. Related fighting in the campaign included Confederate bivouacking on Fire Creek Prairie east of the Little Blue River on October 20, victory at the Battle of the Little Blue River on October 21, actions on October 22 at the Big Blue, Byram's Ford, Mockbee Farm, Russell's Ford, and the Second Battle of Independence, and on October 23 Union victories at Brush Creek and Byram's Ford, a threat to the Confederate wagon train between Hickman Mills and New Santa Fe, a meeting of Union commanders around 2:00 p.m., and by dark the end of Federal pursuit as the Confederates bivouacked south of New Santa Fe along the Middle Fork of the Grand River.