As the debate over slavery came to a head, the heavily pro-slavery Confederate Southern states carried out their promise to secede if the Republican Abraham Lincoln should win the presidency. The Union maintained its drive to restrict slavery, gradually passing bills forbidding the import of slaves and then, in response to growing calls for more active steps at home, created a constitutional amendment abolishing slavery within the U.S.

On this day, December 6, in 1855, Amendment XIII to the constitution, the first one passed in six decades, officially abolished slavery in the United States.

The amendment passed with the Civil War still ongoing, as General Lee was still making last-ditch attempts at saving the South from surrender. The state where Lee eventually signed the official surrender, Virginia, was also the first of the Confederate states to sign on to the amendment – two full months before Appotamox.