The thirteenth amendment of the Constitution of the United States of America officially abolished slavery and prohibited involuntary servitude with the exception of those convicted of a crime. The amendment was proposed on January 31, 1865 and its ratification happened on December 6 of the same year. Previously, in 1863, President Abraham Lincoln, had dictated the Proclamation of Emancipation, which freed slaves from the Confederate states that still continued in absentia.