December 6, 1865: The Thirteenth Amendment is adopted, abolishing slavery.

The large-scale emancipation of American slaves began in 1863, with the issuance of the Emancipation Proclamation, which applied in only ten states and was enacted as a military measure but represented a momentous step toward complete abolition nevertheless. That year, Giuseppe Garibaldi wrote Lincoln to tell him: “Posterity will call you the great emancipator, a more enviable title than any crown could be, and greater than any merely mundane treasure.”

In January of 1864, Senator John B. Henderson of Missouri submitted to the Senate a proposal for a constitutional amendment abolishing slavery. His proposal was combined with proposals made by Senators James Ashley (Ohio), James Wilson (Iowa), and Charles Sumner (Massachusetts). The Senate passed the amendment in April of 1864, and the House of Representatives approved it in January of 1865 after much deliberation (and scheming, politicking, and patronage). Northern states quickly ratified as well, but it took several months for Georgia, the 27th of 36 to ratify, do so, and passage of the amendment was not complete until after Abraham Lincoln’s assassination.

The text of the amendment was straightforward and clear:

Neither slavery nor involuntary servitude, except as a punishment for crime whereof the party shall have been duly convicted, shall exist within the United States, or any place subject to their jurisdiction.

Congress shall have power to enforce this article by appropriate legislation.

Between the Emancipation Proclamation and the Thirteenth Amendment, around four million slaves were freed by the end of the war.