I'm listening to a job talk by Mark A Peterson, one of Bernard Bailyn's last students in American History at Harvard. Peterson is currently working on a fascinating set of issues about the 17th-century Atlantic world.
He argues for a curious connection between coins and slaves. Slaves exist at the intersection between empire and commerce, like coins.
In utopian, city-on-a-hill Boston, slaves were unavoidable in Boston’s relationship to larger trading community. Did slaves belong to Caesar or to God?
Boston's "Pine Tree Shilling" -- an illegal coin in competition with English coins, bearing a tree rather than the image of the English king -- symbolized both New England resistance to London, and Puritan suspicions about rendering to Caesar things (like human faces) that belong to God.
By the 1680s, a few forward-thinking evangelical Protestants like Samuel Sewell and Jonathan Belcher were hoping that Massuchusetts' connection to a larger trading empire was an opportunity for reforming the evils of Atlantic trade through Christian charity.