In June 1777, American Chief Engineer Jeduthan Baldwin and the classically trained Polish engineer Thaddeus Kosciuszko planned and oversaw new defenses on Mount Independence as the Northern Department prepared for the approach of British Lt. Gen. John Burgoyne on Lake Champlain. The southern land approach to the Mount was judged too weak to withstand an enemy encirclement, so work began at three places and soon expanded into three redoubts, an abbatis, and batteries built by hundreds of men. By June 27, platforms were being laid on the batteries on the southeast side of the Mount. Using the rugged terrain and an existing 1776 log and stone breastwork, Kosciuszko and Baldwin created a three-level defensive system in which a front line of cannon was supported by second and third lines, with a camp and two-story blockhouses armed with more cannon farther to the rear. The middle battery was built of stone and sod, with cannon platform foundations near the wall, and traces of nearby building foundations likely came from soldiers' huts erected by British and German troops after the Americans withdrew in July 1777. The three batteries were arranged so their fields of fire intersected, exposing attackers crossing the cleared ground to cannon fire and then musket fire if they came closer. The Americans never tested these works in battle, because they withdrew under cover of darkness on the night of July 5 and 6, 1777. British and German forces then occupied the area and used the defenses from September 19 to 21, when Americans tried to retake Mount Independence and Fort Ticonderoga, before the British themselves withdrew on November 8 after Burgoyne's defeat at Saratoga.