On the 20th of June movements of considerable bodies of the enemy were noticed; and Johnston at once despatched Jackson with his brigade to Martinsburg, with orders to send as much of the rolling-stock of the railroad as could be removed to Winchester, to destroy the rest, and to support Stuart's cavalry when they advanced. A number of locomotives were sent to Winchester along the highroad, drawn by teams of horses. Forty engines and 300 cars were burned or destroyed, and Jackson then advanced and took up his position on the road to Williamsport, the cavalry camp being a little in advance of him. This was pleasant for Vincent, as when off duty he spent his time with his friends and schoolfellows in Jackson's brigade.
On the 2d of July the scouts rode into camp with the news that a strong force was advancing from Williamsport. Jackson at once advanced with the 5th Virginia Infantry, numbering 380 men and one gun, while Stuart, with 100 cavalry, started to make a circuitous route, and harassed the flank and rear of the enemy. There was no intention on the part of Jackson of fighting a battle, his orders being merely to feel the enemy; whose strength was far too great to be withstood even had he brought his whole brigade into action, for they numbered three brigades of infantry, 500 cavalry, and some artillery.
For some hours the little Confederate force skirmished so boldly that they checked the advance of the enemy, whose general naturally supposed that he had before him the advanced guard of a strong force, and therefore moved forward with great caution. Then the Confederates, being threatened on both flanks by the masses of the Federals, fell back in good order. The loss was very trifling on either side, but the fact that so small a force had for hours checked the advance of an army greatly raised the spirits and confidence of the Confederates. Stuart's small cavalry force, coming down upon the enemy's rear, captured a good many prisoners—Colonel Stuart himself capturing forty-four infantry. Riding some distance ahead of his troop to find out the position of the enemy, he came upon a company of Federal infantry sitting down in a field, having no idea whatever that any Confederate force was in the neighborhood. Stuart did not hesitate a moment, but riding up to them shouted the order, "Throw down your arms, or you are all dead men." Believing themselves surrounded, the Federals threw down their arms, and when the Confederate cavalry came up were marched off as prisoners.
Jackson, on reaching his camp, struck his tents and sent them to the rear, and formed up his whole brigade in order of battle. The Federals, however, instead of attacking, continued their flank movement, and Jackson fell back through Martinsburg and halted for the night a mile beyond the town.
Next day he again retired, and was joined six miles further on by Johnston's whole force. For four days the little army held its position, prepared to give battle if the enemy advanced; but the Federals, though greatly superior in numbers, remained immovable at Martinsburg, and Johnston, to the great disgust of his troops, retired to Winchester. The soldiers were longing to meet the invaders in battle, but their general had to bear in mind that the force under his command might at any moment be urgently required to join the main Confederate army and aid in opposing the Northern advance upon Richmond.
Stuart's cavalry kept him constantly informed of the strength of the enemy gathering in his front. Making circuits round Martinsburg, they learned from the farmers what numbers of troops each day came along; and while the Federals knew nothing of the force opposed to them, and believed that it far outnumbered their own, General Johnston knew that Patterson's force numbered about 22,000 men, while he himself had been joined only by some 3,000 men since he arrived at Winchester.
On the 18th of July a telegram from the government at Richmond announced that the Federal grand army had driven in General Beauregard's pickets at Manassas, and had begun to advance, and Johnston was directed if possible to hasten to his assistance. A few earthworks had been thrown up at Winchester, and some guns mounted upon them, and the town was left under the protection of the local militia. Stuart's cavalry was posted in a long line across the country to prevent any news of the movement reaching the enemy. As soon as this was done the infantry, 8,300 strong, marched off. The troops were in high spirits now, for they knew that their long period of inactivity was over, and that, although ignorant when and where, they were on their march to meet the enemy.
They had no wagons or rations, the need for speed was too urgent even to permit of food being cooked. Without a halt they pressed forward steadily, and after two days' march, exhausted and half famished, they reached the Manassas Gap Railroad. There they were put into trains as fast as these could be prepared, and by noon on the 20th joined Beauregard at Manassas. The cavalry had performed their duty of preventing the news of the movement from reaching the enemy until the infantry were nearly a day's march away, and then Stuart reassembled his men and followed Johnston. Thus the Confederate plans had been completely successful. Over 30,000 of the enemy, instead of being in line of battle with the main army, were detained before Winchester, while the little Confederate force who had been facing them had reached Beauregard in time to take part in the approaching struggle.
In the North no doubt as to the power of the grand army to make its way to Richmond was entertained. The troops were armed with the best weapons obtainable, the artillery was numerous and excellent, the army was fed with every luxury, and so confident were the men of success that they regarded the whole affair in the light of a great picnic. The grand army numbered 55,000 men, with 9 regiments of cavalry and 49 rifle-guns. To oppose these, the Confederate force, after the arrival of Johnston's army, numbered 27,833 infantry, 35 smooth-bored guns, and 500 cavalry. Many of the infantry were armed only with shot-guns and old fowling-pieces, and the guns were small and ill-supplied with ammunition. There had been some sharp fighting on the 18th, and the Federal advance across the river of Bull Run had been sharply repulsed; therefore their generals determined, instead of making a direct attack on the 31st against the Confederate position, to take a wide sweep round, cross the river higher up, and falling upon the Confederate left flank, to crumple it up.
All night the Federal troops had marched, and at daybreak on the 21st nearly 40,000 men were in position on the left flank of the Confederates. The latter were not taken by surprise when Stuart's cavalry brought in news of the Federal movement, and General Beauregard, instead of moving his troops toward the threatened point, sent orders to General Longstreet on the right to cross the river as soon as the battle began, and to fall upon the Federal flank and rear.