This movement was a peculiarly daring one, but the strategy of it was brilliant. The detachment of the troops sent to Early seriously weakened the force that Lee had under his command for the defense of the Confederate capital, but he hoped for such results from Early's movement as should again compel the Federal Government to weaken or withdraw Grant's army from the siege of Petersburg. He had twice before succeeded by such tactics in compelling the Army of the Potomac to withdraw from Virginia and stand upon its defense at the North. In both instances as soon as that army had withdrawn Lee himself had moved with all his force to the support of the invading column. There is little doubt that he intended to repeat this operation if Early's threat to Washington should prove effective in compelling Grant's withdrawal from Virginia. But by this time volunteering by hundreds of thousands and drafts, some of which brought as many as half a million men into the field, had so enormously increased the Federal numbers that Grant was strongly disposed to leave the defense of Washington to quite other troops than those he had with him in his operations at Petersburg. The disparity of numbers between the two armies had now become too great to be offset by brilliant strategy, or by any energy in daring enterprise. Hunter had so far carried out Grant's plan of ravaging the Valley of Virginia and moving upon the Confederate lines of communication at Lynchburg, as to create in Lee's mind a serious apprehension. Partly to meet this danger, and partly with a larger strategic purpose, Lee detached Early, and sent him down the Valley with about 8,000 men. Slipping into the upper or southern end of the valley without discovery, Early plunged forward impetuously, and so completely broke Hunter's resistance that that general, instead of retiring before his enemy toward the Potomac, abandoned the field completely, and took refuge in West Virginia, thus leaving Early's pathway to the region beyond the Potomac open and unobstructed. Early was an officer of extraordinary vigor and promptitude. He quickly crossed the Potomac and pushed on to Monocacy near the city of Frederick. There he was met by a force under General Lew Wallace on the ninth of July. Hurling his army upon Wallace he quickly swept him from the field. He then pushed forward until, on the eleventh of July, he came within sight of Washington City itself, and for a time it was gravely feared there that he would enter and possess the Federal capital.