The 13th amendment was passed by the Senate on April 8, 1864 and by the House on January 31, 1865. It marked the official end of slavery in the United States. The Civil War, however, had mortally wounded slavery as an institution, since the Southern economy was devastated and enslaved African Americans had rebeled and run away from plantations in record numbers, greatly diminishing the amount of slaves under Southern control. The greatest strike against slavery, however had been Lincoln's Emancipation Proclamation, which freed all slaves in rebel states. Thus, as soon as a slave left Confederate control, or as soon as the Union army liberated a certain area, that person was no longer a slave. Though it was a unilateral war measure of the Executive branch, and thus did not have the legal standing of a constitutional amendment, the Emancipation changed the legal status of more than 3.5 million slaves, dealing a crippling blow to Southern slavery.