Hospital ships of many types have been part of the United States Navy at least since 1798. Their special status has been internationally recognised under the second Geneva Convention of 1906 and the Hague Convention of 1907. In this list, the particular roles of some hospital ships are identified, e.g. as ambulance vessels, rescue ships, and evacuation ships. Also included are ships that had a dual role, also serving as barracks ships, receiving ships, supply ships or guard ships.