The Thirteenth Amendment to the U.S. Constitution was ratified on December 6, 1865, officially abolishing slavery and involuntary servitude throughout the United States, except as punishment for a crime. The amendment had passed the Senate on April 8, 1864, and the House of Representatives on January 31, 1865, before being sent to the states for ratification. Secretary of State William H. Seward officially certified it on December 18, 1865, marking the formal end of legal slavery in the United States.