The University of Saint Mary's copy of the Thirteenth Amendment is one of 15 known copies signed by Abraham Lincoln.
Several variations of the amendment exist, determined by the signers of the individual copy. USM's is a Senate type, signed by President Abraham Lincoln, Hannibal Hamlin as Vice President and President of the Senate, Schuler Colfax as Speaker of the House of Representatives, and the 36 Senators who voted for the amendment.