Historian Gladys L. Knight describes how leaders who emerged during and after the period in which slavery in the United States was legal often personified the Moses symbol. "The symbol of Moses was empowering in that it served to amplify a need for freedom." Therefore, when Abraham Lincoln was assassinated in 1865 after the passage of the amendment to the Constitution outlawing slavery, Black Americans said they had lost "their Moses". Lincoln biographer Charles Carleton Coffin writes, "The millions whom Abraham Lincoln delivered from slavery will ever liken him to Moses, the deliverer of Israel." Similarly, Harriet Tubman, who rescued approximately seventy enslaved family and friends, was also described as the "Moses" of her people.