The woodcut appeared on the 1837 publication of the American Quaker poet and abolitionist John Greenleaf Whittier's (1807–1892) antislavery poem Our Countrymen in Chains. The design dates back to the 1780s when it was adopted as the seal of the Society for the Abolition of Slavery in England. It also appeared on medallions that the English potter Josiah Wedgwood (1730–1795) made for the society.
"Am I not a man and a brother?", USA, woodcut, 1837, unknown artist; source: Whittier, John Greenleaf: Our Countrymen in Chains, New York: sold at the Anti-Slavery Office, 144 Nassau St. 1837, Library of Congress, Rare Book and Special Collections Division, DIGITAL ID: (digital file from b&w film copy neg. of detail of man and banner) cph 3a44497, LCCN Permalink: http://lccn.loc.gov/2008661312, public domain.