General D. H. Hill guarded the Boonsboro Gap, and Longstreet was ordered to support him, in order to prevent a force from penetrating the mountains at this point, in the rear of McLaws, so as to relieve the garrison at Harper's Ferry. Early on the 14th a large body of the enemy attempted to force its way to the rear of the position held by Hill, by a road south of the Boonsboro and Frederick turnpike. The small command of Hill, with Garland's brigade, repelled the repeated assaults of the army, and held it in check for five hours. Longstreet, leaving a brigade at Hagerstown, hurried to the assistance of Hill, and reached the scene of action between 3 and 4 P.M. The battle continued with great animation until night. On the south of the turnpike the assailant was driven back some distance, and his attack on the center repulsed with loss. Darkness put an end to the contest.
The effort to force the pass of the mountain had failed, but it was manifest that without reënforcements Lee could not hazard a renewal of the engagement; for McClellan, by his great superiority of numbers, could easily turn either flank. Information was also received that another large body of his troops had, during the afternoon, forced its way through Crampton Gap, only five miles in rear of McLaws. Under these circumstances it was determined to retire to Sharpsburg, where we would be on the flank and rear of the enemy should he move against McLaws, and where we could more readily unite with the rest of our army. This movement, skillfully and efficiently covered by the cavalry brigade of General Fitzhugh Lee, was accomplished without interruption. The advance of McClellan's army did not appear on the west side of the pass at Boonsboro until about 8 A.M. on the following morning.
The resistance that our troops had offered there secured sufficient time to enable General Jackson to complete the reduction of Harper's Ferry. The attack on the garrison began at dawn on the 15th. A rapid and vigorous fire was opened by the batteries of General Jackson, in conjunction with those on Maryland and Loudon Heights. In about two hours, the garrison, consisting of more than eleven thousand men, surrendered. Seventy-three pieces of artillery, about thirteen thousand small-arms, and a large quantity of military stores fell into our hands. General A. P. Hill remained formally to receive the surrender of the troops and to secure the captured property.
The commands of Longstreet and D. H. Hill reached Sharpsburg on the morning of the 15th. General Jackson arrived early on the 16th, and General J. G. Walker came up in the afternoon. The movements of General McLaws were embarrassed by the presence of the enemy in Crampton Gap. He retained his position until the 14th, when, finding that he was not to be attacked, he gradually withdrew his command toward the Potomac, then crossed at Harper's Ferry, and marched by way of Shepardstown. His progress was slow, and he did not reach the battle-field at Sharpsburg until some time after the engagement of the 17th began.
At this time the letter, from which the following extract is made, was addressed by me to General R. E. Lee, commanding our forces in Maryland:
"SIR: It is deemed proper that you should, in accordance with established usage, announce, by proclamation, to the people of Maryland, the motives and purposes of your presence among them at the head of an invading army; and you are instructed in such proclamation to make known," etc.
In obedience to instructions, General Lee issued the following address:
"HEADQUARTERS, ARMY OF NORTHERN VIRGINIA, NEAR FREDERICK,
September 8, 1862.
"TO THE PEOPLE OF MARYLAND: It is right that you should know the purpose that has brought the army under my command within the limits of your State, so far as that purpose concerns yourselves.
"The people of the Confederate States have long watched, with the deepest sympathy, the wrongs and outrages that have been inflicted upon the citizens of a Commonwealth allied to the States of the South by the strongest social, political, and commercial ties, and reduced to the condition of a conquered province.