Karlos K. Hill and Soraya Field-Fiorio (TED-Ed narration/content)

And five months later, he announced the Emancipation Proclamation.

It promised freedom to the 3.5 million people enslaved in Confederate states, but it would only be fulfilled if the rebelling states didn't rejoin the Union by January 1, 1863.

And it bore no mention of the roughly 500,000 people in bondage in the border states of Delaware, Maryland, Kentucky, and Missouri that hadn't seceded.

When the Confederacy refused to surrender, Union soldiers began announcing emancipation,

but many southern areas remained under Confederate control, making it impossible to actually implement abolition throughout the South.

The war raged on for two more years, and on January 31st, 1865, Congress passed the 13th Amendment.

It promised to end slavery throughout the U.S., except as punishment for a crime.

But to go into effect, 27 states would have to ratify it first.

Meanwhile, the Civil War virtually ended with the surrender of Confederate General Robert E. Lee on April 9th, 1865.

But although slavery was technically illegal in all Southern states, it still persisted in the last bastions of the Confederacy.

There, enslavers like Kneeling continued to evade abolition until forced.

This was also the case when Union General Gordon Granger marched his troops into Galveston, Texas on June 19th and announced that all enslaved people there were officially free and had been for more than two years.

Still, at this point, people remained legally enslaved in the border states.

It wasn't until more than five months later, on December 6, 1865, that the 13th Amendment was finally ratified.

This formally ended chattel slavery in the U.S.,

Because official emancipation was a staggered process, people in different places commemorated it on different dates.

Those in Galveston, Texas began celebrating Juneteenth, a combination of June and 19th, on the very first anniversary of General Granger's announcement.

Over time, smaller Juneteenth gatherings gave way to large parades, and the tradition eventually became the most widespread of emancipation celebrations.

But while chattel slavery had officially ended,

racial inequality, oppression, and terror had not.