60,000 men of the Union army. It was a risky plan that required careful execution, but Lee knew that he could not win in a battle of attrition or siege against the Union army. The Confederate cavalry under Brig. Gen. J.E.B. Stuart had reconnoitered Porter's right flank as part of a daring circumnavigation of the entire Union army from June 12 to June 15 and found it vulnerable. Stuart's forces burned a couple of Union supply ships and was able to report much of McClellan's army's strength and position to Gen. Lee. McClellan was aware of Jackson's arrival and presence at Ashland Station, but did nothing to reinforce Porter's vulnerable corps north of the river. Lee's plan called for Jackson to begin the attack on Porter's north flank early on June 26. Maj. Gen. A.P. Hill's Light Division was to advance from Meadow Bridge when he heard Jackson's guns, clear the Union pickets from Mechanicsville, and then move to Beaver Dam Creek. The divisions of Maj. Gens. D.H. Hill and James Longstreet were to pass through Mechanicsville, D.H. Hill to support Jackson and Longstreet to support A.P. Hill. Lee expected Jackson's flanking movement to force Porter to abandon his line behind the creek, and so A. P. Hill and Longstreet would not have to attack Union entrenchments. South of the Chickahominy, Magruder and Huger were to demonstrate, deceiving the four Union corps on their front. Opposing forces Union Confederate Battle Lee's intricate plan went awry immediately. Jackson's men, fatigued from their recent campaign and lengthy march, ran at least four hours behind schedule. By 3 p.m., A.P. Hill grew impatient and began his attack without orders. Hill's division, minus Brig. Gen Lawrence O'Bryan Branch's brigade, which was placed off to the north to link up with Jackson, entered Mechanicsville and skirmished with George McCall's Union division, deployed around the town. McCall fell back to an easily defensible spot on the opposite side of Beaver Dam Creek. There, the brigades of Brig. Gen John F. Reynolds and Brig. Gen Truman Seymour dug in, with Brig. Gen George G. Meade's brigade placed behind them in reserve, Reynolds' brigade to the north and Seymour's to the south. On Reynolds' right, the divisions of Brig. Gen George Morell and Brig. Gen George Sykes formed a semicircle. Supporting the roughly 26,000 Union infantrymen were 32 artillery pieces. There, 14,000 well entrenched infantry, supported by 32