Jackson had now completely accomplished his purpose of driving Schenck back upon Fremont. He had no desire to press on and bring about a battle with the united forces of the two in the difficult mountain country. He had effectually prevented a junction of Fremont or Schenck with Banks's army at Harrisonburg. He had prevented the capture of Staunton by the Federals, thus protecting the railroad connections of the Confederates, and he had kept between thirty and forty thousand Federal troops busy in the Valley, who might otherwise have been sent to reinforce McClellan. Still more important, his operations had compelled the Federal Government to stop the advance of McDowell's army by way of Fredericksburg and thus to deprive McClellan, assailing Richmond, of a reinforcement which might have rendered his assault absolutely irresistible. Jackson's next necessity was to unite his meager force with the column of Ewell which was posted at Elk Run for the double purpose of threatening Banks at Harrisonburg and standing ready to march at a moment's warning to the assistance of the beleaguered garrison at Richmond. It was the grandest of grand strategy that Jackson was engaged in, and it was directed by the masterful genius of Robert E. Lee, acting through and by the genius of Stonewall Jackson. Milroy and Schenck had been dislodged from the positions that threatened Staunton. They had been driven westward. They had also been effectually cut off for the time at least from a possible junction with Banks. So Jackson decided to effect the speediest possible junction between his own force in the field and Ewell's command of 8,000 men at Elk Run valley, and with the force thus concentrated to assail Banks at Harrisonburg. He hoped by a precipitate movement to defeat Banks before Fremont, whose plans of campaign he had so greatly interfered with, could come to that general's assistance. But Banks did not wait for Jackson. In face of the fact that his 19,000 men at Harrisonburg outnumbered the whole of Jackson's widely scattered forces, Banks retreated northward down the Valley as soon as Jackson began his campaign. On the first of May he evacuated Harrisonburg and slowly retired to Newmarket. There he lost more than half his force by the detachment of Shields with 11,000 men, who moved on May 12, by way of Luray and Front Royal to join the force at Fredericksburg, thus emphasizing that threat to Richmond which it was Jackson's function to divert. So far Jackson's strategy was unsuccessful. He had defeated Schenck and Milroy. He had prevented a junction of their forces with those of Banks; but he had not prevented Banks from sending 11,000 men and a proportionate number of guns to strengthen the column at Fredericksburg which was intended to join McClellan before Richmond and to render him irresistible. From Newmarket Banks continued his retreat down the valley--northward--until he rested at Strasburg and Front Royal.