But the story of the Valley campaign is not yet fully told. Having driven Fremont back into West Virginia and Banks beyond the Potomac at Williamsport, Jackson was ordered by Lee to make a demonstration threatening an invasion of Maryland and seeming to threaten an assault upon Washington, by way of still further disarranging the Federal plans and diverting Federal forces from the assault upon Richmond.
Jackson moved at once upon Harper's Ferry and for a time seemed not only determined but quite easily able to cross the Potomac there and push forward into Maryland and Pennsylvania or to sweep with enthusiastic fury upon Washington itself.
The result was what Lee had planned that it should be. Fremont, whose force ought to have been moved to McClellan's reinforcement, was ordered to advance from the fastnesses of the West Virginia mountains into the Valley, there to assail Jackson. Banks, driven to cover at Williamsport on the Potomac above Harper's Ferry, was ordered to hold the crossings there against a possible advance of Jackson by that route and presently to return to the Valley and assail Jackson. Saxton, with 7,000 or 8,000 men, withdrawn from McDowell's army, was sent to hold the heights about Harper's Ferry and at the proper time to advance. McDowell's carefully planned march upon Richmond was suspended and the greater part of his force was ordered to the Valley. The purpose was by concurrent action on the part of Fremont moving from West Virginia, Banks moving back up the Valley from Williamsport, Saxton's advancing from the neighborhood of Harper's Ferry, and McDowell's strong column crossing the Blue Ridge from Fredericksburg, completely to surround, overwhelm and destroy Jackson, whose total force was now reduced to a scant 15,000, while the forces thus set to the task of making an end of him, aggregated not less than 55,000 or 60,000 men. It was his task, with 15,000 men not only to meet and destroy these forces in detail, so far as that might be done, but in any case to escape from the trap set for him and unite his army with that of Lee before Richmond in time to lend his enthusiasm and his strength to that assault upon McClellan which was planned for the immediate future.
If the reader will look at a map he will see almost at a glance how perilous a problem Jackson had to solve. With less than 15,000 men he was threatening Harper's Ferry and the strongholds round about, held by Saxton with 7,000 men and eighteen pieces of artillery. Banks with about 9,000 men was now advancing from Williamsport to assail him in flank and rear, and cut off his retreat. Fremont with 10,000 or 15,000 men was advancing from West Virginia and had by telegraph promised Mr. Lincoln that he would be in Strasburg—seventeen miles south of Winchester and commanding Jackson's route of retreat—on Saturday, May 31. In the meanwhile Shields, commanding 20,000 men from McDowell's army and followed by McDowell himself with the rest of it, was hurrying from Fredericksburg into the Valley and was due at Strasburg by noon of the thirty-first.
In other words four armies, numbering in the aggregate more than 50,000 men, were threatening to envelop and overwhelm Jackson. Of these forces no less than 35,000 men were rapidly concentrating in Jackson's rear upon the lines over which he must march in order to escape from the trap set for him and add his force to Lee's in time for the impending battle before Richmond.
It was Jackson's problem not only to escape from these forces, rapidly concentrating to destroy him, but so far to defeat them in detail with his little army as to keep them where they were, while moving his own army to Lee's assistance.
This required grand strategy on a grand scale, and Jackson responded to the demand with a brilliancy wholly unmatched in any other operation of the war. Putting aside details that would only serve to confuse the reader's mind, let us tell in outline the story of what the great commander of the "foot cavalry" did in this complex emergency.
First of all, he withdrew his troops hurriedly from the neighborhood of Harper's Ferry to Winchester. When he got there he found that McDowell's force was in possession of Front Royal, only twelve miles from Strasburg, and Fremont was at Wardensville, only twenty miles away, while the head of his own column was eighteen miles distant from the crucial point, and its rear forty-three miles away. A large part of his force was footsore and exhausted after a hurried march of twenty-five miles in a single day, with frequent skirmishings to punctuate their progress.
Nevertheless Jackson determined to reach and occupy Strasburg before his enemies could get there. He had eighteen miles to go while one of the enemy's columns had twenty and the other only twelve to travel. Their combined forces outnumbered his own about three to one, to say nothing of the 15,000 men of Banks and Saxton who had been pressing his rear all day. But he believed it possible for him, reckoning upon the extraordinary marching qualities of his men, to reach Strasburg before the enemy's columns could concentrate there. If he could do that he counted upon the superb fighting spirit of his men to overcome the enemy's three detachments by striking them separately in spite of the fact that one of those detachments outnumbered him by thirty-three per cent while each of the others nearly or quite equaled him in numbers.
He acted instantly. His march was incumbered by 2,300 Federal prisoners and an embarrassingly large train consisting in its major part of wagons loaded with precious stores which he had captured from the enemy. But in spite of all he marched all the way to Strasburg on the 31st of May, while his rear guard succeeded in passing well beyond Winchester, some parts of it having covered thirty-five miles since the morning. The Federals pursuing under Saxton had stopped at Charlestown, their commander afterwards reporting that their exhaustion was such as to forbid a further advance.