The conception of Fort Sheridan began as a result of the Haymarket affair in May 1886. Chicagoans concerned with the outbreak of violence petitioned Congress to install a military base nearby to Chicago, if the need should arise. Marshall Field led the petition to reserve land for the military base; and 632 acres of land were reserved for Fort Sheridan. In 1894 troops from Fort Sheridan were sent into Chicago during the Pullman Strike. During World War I, Fort Sheridan became a Reserve Officers Training Center. After the war, the fort expanded its duties to treat patients during the 1918 influenza epidemic. During World War II, the fort was a Recruit Reception Center. The fort also served as administrative control headquarters for prisoners of war camps in Illinois, Michigan and Wisconsin. Approximately 15,000 prisoners were placed under their responsibility. During the Korean and Vietnam conflicts, the fort continued as a reception and processing center for military personnel. In the early 1980s, a portion of Fort Sheridan was placed on the National Register of Historic Places. By the mid 1980s, the reduction of military personnel staff began and its function shifted to supervision of reserve activities around the Midwest. By the early 1990s, the Deptartment of Defense downsized: Fort Sheridan was among the first to be closed during the first round of military base closures. However, the Fort continued to support troops during Desert Storm and Desert Shield until it officially closed in 1993.