In March McClellan, who had been lying inactive so long, began his noted Peninsula campaign which terminated in utter failure. His advance was opposed by Gen. J. E. John ston, who gradually fell back toward Richmond till he reached Seven Pines, or Fair Oaks. Here the armies met on 31 May. The timely arrival of Sumner's corps from the other side of the Chidcahominy saved McClellan from serious disaster. Johnston being badly wounded, Gen. G. W. Smith succeeded to the command tem porarily. On 2 June Gen. R. E. Lee was as signed to the command of the Army of North ern Virginia, which he retained till the close of the war. Gen. ((Stonewall' Jackson (q.v.), by a brilliant campaign in the valley, in which he defeated Banks at Winchester, forcing him across the Potomac, Fremont at Cross Keys, and Shields at Fort Republic, held most of McDowell's corps around Fredericksburg, thus preventing them from joining McClellan, and himself suddenly appeared, 25 June, at Ashland, on the flank of McClellan's army in front of Richmond. Thereupon followed the Seven Days' battles, beKinning with Mechanicsville 26 June, and including Gaines' Mill and Malvern Hill, after ,which McClellan withdrew to Har rison's Landing on the James. The campaign proved a disastrous failure; and McClellan, having been relieved, 11 March, of the general command of the armies, now retained that of the Army of the Potomac and saw Halleck as signed to the chief command, 23 July.
After the withdrawal of the Army of the Potomac to the James, McClellan, against his protest, was recalled from the Peninsula to the vicinity of Washington. General Pope was now ordered to organize the corps of McDowell, Banks and Fremont into the Army of Virginia, to cover this movement and to protect Wash ington. With this army Pope advanced against the Confederate 'forces near Gordonsville, where, confronted by Lee and Longstreet, he retired behind the Rappahannock and was de feated at the second battle of Bull Run, 30 August. He then withdrew to Centreville, where he was reinforced by the corps of Sum ner and Franklin from McClellan's army. His flank was attacked by Jackson at Chantilly. On 2 September Pope was recalled with his army to Washington and was relieved of. his com mand, his forces being added to the Army the Potomac under McClellan.
In September Lee set out for his invasion of the North, crossing the Potomac near Lees burg and moving toward Frederick. He cap tured Harper's Ferry and advanced to Hagers town, thence retiring to Sharpsburg, where he was met by Hooker's corps of McClellan's army. A desperate fight ensued, 17 September in which the losses were greater for one day's fighting than in any other battle of the war. Lee then withdrew across the Potomac, Mc Clellan's army following him into Virginia, and resumed his position beyond the Rappahan nock. Near Warrenton McClellan was super
seded, 7 November, by Gen. Ambrose E. Burn side. Burnside took his position opposite Lee's army near Fredericksburg, and on 13 Decem ber attempted to cross the Rappahannock and assault Marye's Heights, only to be repulsed with terrific slaughter. The following month he undertook to cross the river above Freder icksburg and turn Lee's left, but the attempt proved a dismal failure, being known as the great Mud March. Thereupon Burnside was relieved of his command and was succeeded by Hooker, 26 Jan. 1863.
The winter of 1863 was spent in laborious, though fruitless efforts to capture Vicksburg, which, because of its strategic importance, the Confederates held strongly fortified. Grant and Sherman both failed. At length, in April, Grant began his second move upon the city from the south and east. Admiral Porter's fleet convoying the transports ran the batteries on the night of 16 April, and the advance of the army crossed the river, 30 April. On 1 May Port Gibson was captured and Grant had forced his way to the rear of Vicksburg. Preventing a junction of Pemberton's and Johnston's forces, Grant defeated the former at Champion's Hill, and again at Big Black Ridge, 18 May, pursuing him into Vicksburg. After two unsuc cessful assaults upon the fortifications, Grant undertook the siege of the city, which surren dered, 4 July 1863. This event was a turning point in the war in the West, hardly less im portant than Gettysburg in the East. Hooker opened the campaign of 1863 in the Army of the Potomac by crossing the Rappahannock at Fredericksburg and advancing to the Rapidan. At Chancellorsville the Union right was disas trously routed by Jackson's corps, 2 May. In the night, while reconnoitering before his pick ets, Jackson was mortally wounded by his own men, who mistook him for the enemy. On the following day Hooker was forced back, with heavy loss, and recrossed the river, 5 May. Hooker being utterly defeated, Lee set out from Fredericksburg, on 3 June, for a second invasion of the North. The advance under Ewell, after some minor engagements in the valley, crossed the Potomac at Williamsport, 15-16 June, and moved on to Chambersburg and the vicinity of Harrishurk and Columbia, cap turing York on 28 June. Ewell was then or dered to fall back to Gettysburg, where Lee was concentrating his army. The Army of the Potomac under Hooker had advanced mean while to Frederick, where Hooker requested to be relieved; and Meade was •assigned to the command. The two armies encountered each other at Gettysburg and after a three days' bat tle, 1-3 July, Lee retreated and recrossed the Potomac, without a battle. After a month's rest in the Shenandoah, Lee resumed his former position below the Rappahannock, Meade following him thither.