In 1864, the Confederate Army imprisoned 50 Union Army officers as human shields against federal artillery in the city of Charleston, South Carolina, in an attempt to stop Union artillery from firing upon civilians in the city. In retaliation, United States Secretary of War Edwin M. Stanton ordered six hundred captured Confederate officers to be taken to Morris Island, South Carolina, at the entrance to Charleston Harbor and used as human shields for forty-five days in an attempt to silence the Confederate gunners manning Fort Sumter. These men became known in the South as the Immortal Six Hundred.