Dred. Dred Scott, an American black slave. He became famous because a case he was suspected of triggered the abolitionist movement in American history. In this case, the famous American lawyer Roswell? Roswell Field defended Scott and finally won his freedom. However, on March 6, 1857, the Supreme Court sentenced Dred? In Scott's case, only Scott was declared free, but all blacks were denied citizenship, and it was claimed that Congress could not ban slavery. This led to the discussion of slavery in free States and opened the prelude to the abolition of slavery in the United States.