This image is one of the earliest symbols of slavery's oppression, created to depict the degredation of the slave trade.
When the Quaker-led Society for Effecting the Abolition of the Slave Trade met in London, in 1787, three members were asked to develop a design which could serve as the Society's seal.
An image, depicting an "African in Chains in a Supplicating Posture," was selected. "Am I Not A Man and A Brother?" were the words surrounding him.
Josiah Wedgwood (then a Society member) made the emblem at his pottery factory. No one knows for sure who designed and engraved the seal, but historians attribute the design to either William Hackwood or Henry Webber. They both worked at Wedgwood's factory.
PBS tells us how the emblem reached America:
In 1788, a consignment of the [Wedgwood] cameos was shipped to Benjamin Franklin in Philadelphia, where the medallions became a fashion statement for abolitionists and anti-slavery sympathizers. They were worn as bracelets and as hair ornaments, and even inlaid with gold as ornaments for snuff boxes. Soon the fashion extended to the general public.
Image, courtesy Library of Congress.