By the early 1800s, a growing number of people in the United States and Europe began to openly question the morality of slavery. The abolitionist movement, which sought to end slavery, had been active since the late 1700s, but it gained momentum in the early 1800s as more and more people began to speak out against the institution.
In the United States, the abolitionist movement was led by individuals such as William Lloyd Garrison, Frederick Douglass, and Sojourner Truth. These and other abolitionists argued that slavery was a violation of the fundamental human rights of the enslaved, and they worked to end the practice through a variety of means, including lobbying for legislative change, organizing boycotts, and publishing anti-slavery literature.
In Europe, the abolitionist movement was also gaining support. Many Europeans were horrified by the brutal treatment of slaves in the Americas, and they joined the movement to end slavery. Some European countries, such as Britain, had already abolished the slave trade, and by the early 1800s, they were working to end slavery in their colonies as well.