Opposite McDowell, at Manassas Junction, about thirty miles from Washington, lay a Confederate army under Brigadier-General Beauregard who, three months before, had won the homage of the South by reducing Fort Sumter. Opposed to Patterson in the Shenandoah valley was Joseph E. Johnston with a force of nine thousand men. The plans of the President and General Scott were to send McDowell against Beauregard, while Patterson was to detain Johnston in the Valley and prevent him from joining Beauregard. It was confidently believed that, if the two Confederate forces could be kept apart, the "Grand Army" could win a signal victory over the force at Manassas; and on July 16th, with waving banners and lively hopes of victory, amid the cheers of the multitude, it moved out from the banks of the Potomac toward the interior of Virginia. It was a motley crowd, dressed in the varied uniforms of the different State militias. The best disciplined troops were those of the regular army, represented by infantry, cavalry, and artillery. Even the navy was drawn upon and a battalion of marines was included in the Union forces. In addition to the regulars were volunteers from all the New England States, from New York and Pennsylvania and from Ohio, Michigan, and Minnesota, organizations which, in answer to the President's call for troops, had volunteered for three months' service. Many were boys in their teens with the fresh glow of youth on their cheeks, wholly ignorant of the exhilaration, the fear, the horrors of the battle-field. Onward through the Virginia plains and uplands they marched to the strains of martial music. Unused to the rigid discipline of war, many of the men would drop out of line to gather berries or tempting fruits along the roadside, or to refill their canteens at every fresh stream of water, and frequent halts were necessary to allow the stragglers to regain their lines. After a two days' march, with "On to Richmond" as their battle-cry, the army halted at the quiet hamlet of Centreville, twenty-seven miles from Washington and seven miles from Manassas Junction where lay the waiting Confederate army of similar composition--untrained men and boys. Men from Virginia, from North and South Carolina, from the mountains of Tennessee, from Alabama, Mississippi, and Georgia, even from distant Arkansas, had gathered on the soil of the Old Dominion State to do battle for the Southern cause. Between the two armies flowed the stream of Bull Run, destined to give its name to the first great battle of the impending conflict. The opposing commanders, McDowell and Beauregard, had been long-time friends; twenty-three years before, they had been graduated in the same class at West Point.