French and American troops having assembled in overwhelming force, from points as far distant as Rhode Island and the West Indies, Washington assumed command of the whole and moved on Yorktown. I have not leisure to give a particular account of our proceedings, it must suffice only to inform you, that, after assembling all the Troops at _Williamsburg_, and making the necessary Arrangements, the Allied Army moved on the Morning of the 28th Sept. and took post in the neighbourhood of York that night. The Enemy gave us no annoyance on the March; a body of Horse that was paraded in front of their Works retired upon our firing a few shot among them. The 29th. was spent in reconnoitring, and taking a position as near the advanced Works as could be done without placing the Encampments directly in the range of the Enemy’s shot; some skirmishing happened between our Riffle men and the Yagers, in which the former had the advantage. At night, the Enemy abandoned all their Out Posts (some of which were very advantageous) and retired to the Town. Yesterday Morning we occupied the same ground and last night made some lodgments at a short distance from the Lines. The Horses and Teams are beginning to arrive from the Northward, the heavy Artillery will be brought up as soon as possible and the Seige pushed with vigor; as I have no Idea that Lord Cornwallis will surrender so respectable a force, as he has under his command, unless he is compelled by dire necessity. WASHINGTON TO MAJOR GENERAL WILLIAM HEATH, OCTOBER 1, 1781. 6. THE FIRST PARALLEL The siege operations of the eighteenth century were conducted according to a set pattern. When the most advantageous ground had been chosen and marked, the besiegers began digging a line of entrenchments facing the besieged position at a distance of from 800 to 1,000 yards, convenient range for the artillery of that day. This line of entrenchments, in which batteries were erected, was known as the “first parallel.” In planning the siege of Yorktown, the allied engineers chose for the first parallel a line from the head of a deep ravine, which half encircled the town on the left, to the York River on the right. Its opening was delayed for several days pending the arrival of heavy artillery. The reconnoissance completed, the artillery disembarked, and the necessary supplies arranged, the establishment of the first parallel was begun. The strength and reputation of the Garrison were the reason for the decision to establish it at the usual distance, and to fortify it by redoubts against sorties. The advanced works on the enemy’s left made it necessary even to increase the distance of the right of the attacks from the body of the place. The lay of the ground determined its outline; the right resting on the steep bank of the river, on the left of the great ravine.