Indecisive as this battle was, it is ever to be memorable as, on its issue, President Lincoln kept a promise to "himself and his Maker."( 3) On September 22, 1862, five days later, he issued a preliminary proclamation announcing his purpose to promulgate, January 1, 1863, a war measure, declaring free the slaves in all States or parts of States remaining at that time in rebellion. He had long before the battle of Antietam contemplated taking this action, and hence had prepared this proclamation, and promised himself to issue it on the Union Army winning a victory. The driving of Lee's army out of Maryland, and thus relieving Washington from further menace, was accepted by him as a fulfilment of the self-imposed condition. McClellan was relieved of the command of the Army of the Potomac while at Orleans, Virginia, November 7, 1862, and Burnside became his successor. McClellan never again held any command. Burnside moved the army to Falmouth, Virginia, opposite Fredericksburg, on the Rappahannock. Though only urged to prepare for the offensive, he precipitated an attack on the Confederate Army, then strongly intrenched on the heights of Fredericksburg. He suffered a disastrous repulse (December 14, 1862) and next day withdrew his army across the Rappahannock to his camps. Burnside was relieved of the command of the Army of the Potomac January 25, 1863, and Major-General Joseph Hooker succeeded him. The battle of Chancellorsville was fought, May 1 to 5, 1863, in the Wilderness country, south of the Rapidan, and resulted in the defeat of the Union Army and its falling back to its former position at Falmouth. The defeats at Fredericksburg and Chancellorsville led to a general belief that another invasion of the North would be made by Lee's army. Such an invasion involved Milroy's command at Winchester, then in the Middle Department, commanded by Major-General Robert C. Schenck, whose headquarters were at Baltimore. This much in retrospect seems necessary to give a better understanding of the events soon to be mentioned.