In 1863, in the middle of the Civil War, President Abraham Lincoln issued the Emancipation Proclamation. The Emancipation Proclamation declared that slaves living in the southern or Confederate states were free. Many slaves joined the Union army. In 1865, the Civil War ended and the southern slaves kept their right to be free. The Emancipation Proclamation led to the 13th Amendment to the Constitution, which ended slavery in all of the United States.