Simplify the following text for a Grade 7 native English-speaking person.
Original: Dred Scott ( 1799 â `` September 17 , 1858 ) was a slave in the United States of America who took legal action to get his freedom in the Dred Scott V. Sandford Case .
Simplified: Dred Scott ( 1795 â `` September 17 , 1858 ) , was an African-American slave in the United States who sued unsuccessfully for his freedom and that of his wife and their two daughters in the Dred Scott v. Sandford case of 1857 .