Prologue: The Curtis Appointment
After being appointed commander of the Federal Department of the Missouri on November 9, 1861, Major General Henry W. Halleck soon realized that he had major problems in Missouri. As long as the Missouri State Guard, commanded by Major General Sterling Price, was a viable fighting force, Halleck would have to dedicate Union troops and resources to counter this threat.
Union Major General Henry Halleck appointed Brigadier General 
Samuel R. Curtis as the commander of the District of Southwestern Missouri on December 25, 1861.
“By order of Major-General Halleck: Brig. Gen. S. R. Curtis is assigned to the command of the Southwestern District of Missouri, including the country south of the Osage and west of the Meramec River.”
Halleck's instructions to Curtis were clear – pursue Price's army and destroy his ability to conduct military operations in the State of Missouri.
Arriving in Rolla, Missouri on Thursday, December 26th, Curtis got off to a rocky start in his new command. Brigadier General Franz Sigel, the commanding officer in Rolla, had not yet received a copy of Halleck's order placing Curtis in command. Sigel felt he was the superior officer in Rolla and refused to take Curtis's word of his appointment. When Halleck's order appointing Curtis to command the District of Southwestern Missouri, Sigel initially resigned but then eventually agreed to serve under Curtis's command.