In 1861, the United States of America divided into two groups. One group included the southern states and was called the Confederacy. The northern states grouped together into the Union. The southern states supported slavery and did not want the federal government to make important decisions about their internal affairs.
The northern states were against slavery. This led to the American Civil War where both sides fought against each other. By the start of 1863, the Union had secured many victories. So President Abraham Lincoln thought that it was a good time to issue the Emancipation Proclamation.
Until 1863, there had been millions of slaves in USA. Most of these were owned by people in the southern states controlled by the Confederacy at the time. The Emancipation Proclamation simply said that all the slaves in the Confederacy-controlled states were free, now and forever.
President Abraham Lincoln issued the Emancipation Proclamation on January 1, 1863. He had been getting ready to issue it since September, 1862. That was because in September, the Union army had secured a major victory against the Confederate army.
Lincoln knew that if he issued the Proclamation after a major victory for the Union, it would be far more effective. After the Union victory at the Battle of Antietam in September, 1862, he started working on the Proclamation and finally announced it on the first day of the following year.
At the time, there were millions of slaves in USA, most of them of African descent. Most of them were in the southern states. But some of these slaves were also in Union-controlled states.
The Emancipation Proclamation said that all the slaves in the Confederacy-controlled states were free but that the slaves in Union-controlled areas had to wait for their freedom until the Union had won the war. The exact part of the Emancipation Proclamation which granted freedom to the slaves read as follows,
Section 1. Neither slavery, not involuntary servitude, except as a punishment for crime, whereof the party shall have been duly convicted, shall exist within the United States, nor any place subject to their jurisdiction.
As a result of the Emancipation Proclamation, millions of slaves in the southern states became free. Of course, they had to reach in the Union-controlled areas to actually become free or wait for the Union armies to take over their states before they could gain freedom. Before the end of the Civil War, millions of slaves were already free and nearly 200,000 of freed African-Americans were fighting alongside the Union armies.
The Emancipation Proclamation further strengthened the Union and weakened the Confederacy. European powers such as Great Britain and France welcomed the proclamation. The Proclamation was an executive order from the President and it took the U.S. Congress another few years to make it a proper part of the Constitution through the 13th Amendment. This happened in December, 1865.