 The 1688 Petition was the first American public document of its kind to protest slavery, and in addition was one of the first public documents to define universal human rights.The American Colonization Society, the primary vehicle for returning black Americans to greater freedom in Africa, established the colony of Liberia in 1821–23, on the premise that former American slaves would have greater freedom and equality there.The ACS assisted in the movement of thousands of African Americans to Liberia, with its founder Henry Clay stating; "unconquerable prejudice resulting from their color, they never could amalgamate with the free whites of this country.