By the end of August, Davis received orders to succeed Brigadier General Ulysses S. Grant as commander of forces in northwestern Missouri. His headquarters were in Jefferson City, Missouri, with approximately 16,000 Confederate troops nearby. General Fremont had great concerns that the Confederate troops, commanded by Generals McCullough and Sterling Price, would set their eyes on St. Louis as a potential target. Davis's command grew quickly, starting at 12,000 at the beginning of September and expanding to 18,000 to 20,000 by the end of the month. Initially, Davis spent time building fortifications to fend off possible attack on the capital city. Once his defensive plan had been completed, he planned an offensive campaign, but materiel was refused to Davis. That may have contributed to losing the Battle of Lexington.