McClellan continued to drill and train his army through the fall of 1861, and well into the following year. It numbered nearly 200,000 men and was one of the finest organizations in the world. In reply to the expressions of impatience, the commander invariably replied that a forward movement would soon be begun, but the weeks and months passed and the drilling went on, and nothing was done. Finally, the government gave the commander to understand that he must advance. McClellan's plan was to move against Richmond, from the lower part of Chesapeake Bay, by way of Urbana on the Rappahannock. While this had many advantages, its fatal objection in the eyes of the President was that it would leave Washington unprotected. He issued an order on the 27th of January directing that on the 22d of February there should be a general land and naval movement against the enemy's position on the Potomac, and that, after providing for the defense of Washington, a force should seize and occupy a point upon the railway to the southwest of Manassas Junction. McClellan was offended by the act of the President and protested, but Mr. Lincoln clung in the main to his plan, and, since the delay continued, he issued orders directing the formation of the army into corps and naming the generals to command them. Another order made arrangements for the intended advance, and it was left to McClellan to carry them out. [Illustration: LIBBY PRISON IN 1884, BEFORE ITS REMOVAL TO CHICAGO.] Reliable information reached Washington that General Joseph E. Johnston, commander of the Confederate forces at Manassas, was engaged in withdrawing his lines with a view of taking a stronger position nearer Richmond. General McClellan began a forward movement with the Army of the Potomac on the 10th of March. The truth was that Confederate spies in Washington had apprised Johnston of the intended advance of McClellan from the lower Chesapeake, and his action was with a view of checkmating the Union commander. Instead of carrying out this plan, McClellan marched to Centreville and occupied the vacated intrenchments of the enemy. The general hope was that Johnston would be forced to give battle, but the roads in Virginia, at that season, were one sea of mud, which made progress so slow that the Confederates had time in which to withdraw at their leisure. Crossing the Potomac into Virginia, with the main army, McClellan made his first headquarters at Fairfax Court-House. About that time he received news that he was relieved of the command of the other departments, his authority being confined to the direction of the Army of the Potomac. He was directed by the President to garrison Manassas securely, see that Washington was protected, and, with the rest of his force, assume a new base at Fort Monroe, or "anywhere between here and there," and, above all things, to pursue the enemy "by _some_ route."