of the surrender, Union forces repaired the fort, and all shipping into and out of Savannah ceased. The loss of Savannah as a viable Confederate port crippled its war effort. With the Fort securely in Union control, General David Hunter, commander of the Union garrison issued General Order Number 7, which stated that all slaves in Florida, Georgia, and South Carolina were now free. President Abraham Lincoln quickly rescinded the order but later issued his own Emancipation Proclamation in 1863. Fort Pulaski was made a final destination on the Underground Railroad, as slaves throughout the area were freed upon their arrival to Cockspur Island. The garrison of Union soldiers reached 600 during the initial occupation, but as the war dragged on, Southern forces would obviously not be able to retake the fort. The garrison was later reduced to about 250. Late in the war, the fort was turned into a prison for a group of captured Confederate officers known as "The Immortal Six Hundred." Thirteen of the men would die at the fort. After the war ended, Fort Pulaski continued briefly as a military and political prison. It would house a Confederate Secretary of State, Secretary of the Treasury, Secretary of War, Assistant Secretary of War as well as three state governors, a senator, and the men who had commanded the fort after it had been taken by the South. Postwar Between 1869 and 1872 the demilune to the rear of the Fort was covered with powder magazines, and the few gun positions that were left were enlarged for heavier guns. By the turn of the 20th century, the fort began to fall into disrepair. In an effort to save the old fort, the War Department finally declared Fort Pulaski a National Monument on October 15, 1924, by presidential proclamation of Calvin Coolidge. The monument was transferred from the War Department to the National Park Service on August 10, 1933. Repairs were then started, and members of the Civilian Conservation Corps arrived on Cockspur Island and began rehabilitation of the fort. Fort Pulaski was opened to the public only for a short time before the beginning of World War II, which would see further use of Cockspur Island as a section base for the US Navy. After the war, Fort Pulaski reverted to the control of the Park Service and was administratively listed on the National Register of Historic Places