Fatal was the mistake which retained McDowell’s divisions in the Valley, and sent Shields in pursuit of Jackson.  While the Federal army, waiting for reinforcements, lay astride the noisome swamps of the Chickahominy, Lee was preparing a counterstroke on the largest scale.

The first thing to do was to reduce the disparity of numbers; and to effect this troops were to be brought up from the south, Jackson was to come to Richmond, and McDowell was to be kept away.  This last was of more importance than the rest, and, at the same time, more difficult of attainment.  Jackson was certainly nearer to Richmond than was McDowell; but to defeat McClellan would take some time, and it was essential that Jackson should have a long start, and not arrive upon the battlefield with McDowell on his heels.  It was necessary, therefore, that the greater part of the latter’s force should be detained on the Shenandoah; and on June 8, while Cross Keys was being fought, Lee wrote to Jackson:  “Should there be nothing requiring your attention in the Valley, so as to prevent you leaving it in a few days, and you can make arrangements to deceive the enemy and impress him with the idea of your presence, please let me know, that you may unite at the decisive moment with the army near Richmond.  Make your arrangements accordingly; but should an opportunity occur of striking the enemy a successful blow, do not let it escape you.”

June 11.

At the same time a detachment of 7000 infantry was ordered to the Valley.  “Your recent successes,” wrote Lee on the 11th, when the news of Cross Keys and Port Republic had been received, “have been the cause of the liveliest joy in this army as well as in the country.  The admiration excited by your skill and boldness has been constantly mingled with solicitude for your situation.  The practicability of reinforcing you has been the subject of gravest consideration.  It has been determined to do so at the expense of weakening this army.  Brigadier-General Lawton with six regiments from Georgia is on his way to you, and Brigadier-General Whiting with eight veteran regiments leaves here to-day.  The object is to enable you to crush the forces opposed to you.  Leave your enfeebled troops to watch the country and guard the passes covered by your cavalry and artillery, and with your main body, including Ewell’s division and Lawton’s and Whiting’s commands, move rapidly to Ashland by rail or otherwise, as you may find most advantageous, and sweep down between the Chickahominy and the Pamunkey, cutting up the enemy’s communications, etc., while this army attacks McClellan in front.  He will then, I think, be forced to come out of his intrenchments, where he is strongly posted on the Chickahominy, and apparently preparing to move by gradual approaches on Richmond."* (* O.R. volume 12 part 3 page 910.)