In the 1600's Penn, along with Roger Williams (1604?-1683) introduced the concept of separation of church and state in America. Roger Williams was a Puritan minister who described himself as a "Seeker" after the true church. He opposed Rev. John Cotton's concept of a Christian theocracy. Cotton's state of Massachusetts punished the following crimes by death: blasphemy, idolatry, witchcraft, heresy, worshipping a graven image and he proposed banishment of anyone who disagreed with the established church. Roger Williams was banished, but escaped. He became impressed with the religious tolerance of the Native Americans. He wrote "The Bloudy Tenet of Persecution" which argued that everyone had the natural right of religious liberty.
The Society of Friends (Quakers) was one of the first religious groups to speak out against slavery. Another was the Mennonites of Germantown, Pennsylvania who adopted a resolution challenging slavery in 1688.
Most other white churches were using the Bible as "proof" that the black race was cursed and that slavery brought them "within the reach of God's grace". Attempts were also made to convert slaves to Christianity, including requiring them to obey Sabbath laws.
From 1629 to 1661, Pope Urban VIII in 1629, Pope Innocent X in 1645 and Pope Alexander VII in 1661 were all personally involved in the purchase of Muslim slaves. In the late 1600's, Roman Catholic theologian Leander wrote,
"It is certainly a matter of faith that this sort of slavery in which a man serves his master as his slave, is altogether lawful. This is proved from Holy Scripture... persons captured in war pass into the ownership of the captors... All theologians are unanimous on this." (Leander, "Quaestiones Morales Theologicae," Lyons 1668 - 1692, Tome VIII, De Quarto Decalogi Praecepto, Tract. IV, Disp. I, Q. 3. )Evangelical Christians in Great Britain eventually joined the abolitionist movement, but not until 1787 when they joined with the Quakers in the formation of the Society for the Abolition of the Slave Trade.
