In the United States, there was a movement to resettle American free blacks and freed slaves in Africa. The American Colonization Society was founded in 1816 in Washington, DC for this purpose, by a group of prominent politicians and slaveholders. But its membership grew to include mostly people who supported abolition of slavery. Slaveholders wanted to get free people of color out of the South, where they were thought to threaten the stability of the slave societies. Some abolitionists collaborated on relocation of free blacks, as they were discouraged by discrimination against them in the North and believed they would never be accepted in the larger society. Most African Americans, who were native-born by this time, wanted to improve conditions in the United States rather than emigrate. Leading activists in the North strongly opposed the ACS, but some free blacks were ready to try a different environment.

What is "the american colonization society"?