General John Thomas and about 2,500 troops quietly marched to the top of Dorchester Heights, hauling tools, the prefabricated fortifications and cannon placements. Hay bales were placed between the path taken by the troops and the harbor in order to muffle the sounds of the activity. Throughout the night, these troops and their relief labored at hauling cannon and building the parapet overlooking the town and the harbor. General Washington was present to provide moral support and encouragement, reminding them that March 5 was the sixth anniversary of the Boston Massacre. By 4 a.m., they had constructed fortifications that were proof against small arms and grapeshot. Work continued on the positions, with troops cutting down trees and constructing abbatis to impede any British assault on the works. The outside of the works also included rock-filled barrels that could be rolled down the hill at attacking troops.