 Complete the following phrase:  After a lengthy interlude with little military activity, McClellan marched his army across the Potomac River starting on October 26. On November 7, Lincoln replaced McClellan with Burnside. On November 15, Burnside began moving his army south towards Fredericksburg, Virginia, midway between the opposing capitals. On November 18, Longstreet began marching his men out of army headquarters in Culpeper towards Fredericksburg, where the Confederate army would 