The Emancipation Proclamation was an executive order issued by President Abraham Lincoln during the Civil War.

It was issued in two parts, a preliminary proclamation in September 1862 and the final version which took effect on January 1, 1863.

The proclamation declared that all enslaved people in the Confederate states that were still in rebellion 'shall be then, thenceforward, and forever free.'

Crucially, it did not apply to enslaved people in the loyal border states or in areas of the South already under Union control.

Lincoln issued it as a 'fit and necessary war measure' to weaken the Confederacy's ability to wage war.

It fundamentally transformed the purpose of the war, making the abolition of slavery an explicit war aim.

The proclamation also authorized the recruitment of African American soldiers into the Union Army.

It was a major diplomatic success, as it made it much more difficult for anti-slavery nations like Britain and France to support the Confederacy.

While it did not immediately free a single slave, it was a crucial step toward the ultimate abolition of slavery.

The complete abolition of slavery throughout the United States was achieved with the passage of the 13th Amendment to the Constitution in 1865.