Josiah Wedgwood was not just famous for being quite the potter, he was also known for being a fervent abolitionist. He managed to use his artwork to bring attention to the cause he was so passionate about. In 1787 the Society for Effecting the Abolition of the Slave Trade formed, their logo was a slave in chains kneeling with the words, "Am I Not a Man and a Brother?" underneath. Wedgwood took the seal and created it in cameo-form, making a large amount to be distributed.
Luckily, the enlightened appeal was a big hit. Ladies would set the medallions in bracelets or set them in hair pins. Wedgwood's cameo was the 18th century version of the Livestrong bracelet, it was fashionable to show your support for a cause.
Like many fashions for a cause, though, the medallion's longevity meant a loss in meaning for many wearers. However, Wedgwood's effort did help in the abolitionist movement and in 1807 Parliament voted to abolish slave trade.