Video: 'The Emancipation Proclamation: Abraham Lincoln and Executive Power, Part 12'

(Monday, September 22, 1862, during the American Civil War) — Five days after Union troops turned back a Confederate invasion of Maryland in the Battle of Antietam — sometimes cited as the bloodiest day in all of American history with a combined tally of 22,717 dead, wounded, or missing — U.S. President Abraham Lincoln today issued a preliminary Emancipation Proclamation, declaring that than three million black slaves in areas still in rebellion as of January 1, 1863 would be free.

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Lincoln, who was residing at the Soldier’s Home, called his cabinet into session today and issued the Preliminary Emancipation Proclamation.

According to Civil War historian James M. McPherson, Lincoln told cabinet members, “I made a solemn vow before God, that if General Lee was driven back from Pennsylvania, I would crown the result by the declaration of freedom to the slaves.”

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Lincoln had first shown an early draft of the proclamation to Vice President Hannibal Hamlin, an ardent abolitionist, who was more often kept in the dark on presidential decisions.

The final proclamation would be issued on January 1, 1863.