She is one of the heroines of African American history and one of the most well-known women of her time. School and youth books recount her deeds. As early as 1869, a first biography was written based on conversations. American biographers compare her to Joan of Arc and Florence Nightingale. Her supporters and friends, more than 300 freed slaves whom she brought as a "Conductor" along the secret routes of the "Underground Railroad" to safety in the North and Canada, called her Moses or, in reference to her work as a scout and spy during the Civil War, General Tubman. She always carried a pistol with her during her dangerous missions. If one of her charges faltered or wanted to turn back, she would hold the pistol to their head: "Go or die!" she declared.