Pope saw the fires at Manassas Junction but believed that it meant Jackson was desperate; he ordered his corps to march on Manassas from the south, east, and north. Pope knew that Longstreet was moving north towards Thoroughfare Gap but did not detach any force to delay him, believing that the Union army could defeat Jackson before Longstreet could arrive. The defeat of Taylor's force convinced George B. McClellan, commanding the Union forces in Washington, not to send any further reinforcements to Pope unless they had artillery and cavalry.