Fort Monroe was built by a huge work force of thousands of people who helped plan and construct the fort, completing it in 1834. This work force included free and enslaved blacks, contract laborers, army personnel, and military convicts. The immense undertaking required large numbers of skilled craftsmen and general laborers, with skilled workers serving as stone and brick masons, carpenters, plasterers, and boatmen. The work was not easy, and laborers faced serious injuries, illness, and even death during the course of the work day. Lieutenant Colonel Charles C. Gratiot was the supervising engineer during the initial phases of construction. During his tenure from 1831 to 1834, U.S. Army Engineer 2nd Lieutenant Robert E. Lee was responsible for the final stages of Fort Monroe's construction. By November 1823, work shown on a site plan had already been completed.