The service of blacks in the U.S. military can be traced back to the Revolutionary War. However, up to the end of World War I, African Americans in military branches were relegated to cooking and cleaning duties. As the United States prepared to enter World War II, pressure to admit African Americans into full service in the military increased due to political maneuvering and social pressure from the African-American community. In addition, a shortage of manpower led the military to employ blacks in all areas of service. However many black servicemen served in segregated camps and received segregated training. The Navy resisted racial integration, but the initial inclusion of blacks in the Navy was first accomplished by creating all-black Navy bands for service across America. During 1942 to 1945, more than 5,000 African-American Navy musicians received musical training at the segregated Great Lakes Training Camps because the Naval School of Music, the designated music training camp for musicians, was closed to blacks. These all-black Navy bands became ambassadors for the Navy and representatives of social change in America.