In 1641, Massachusetts became the first colony to allow slavery through law. Massachusetts passed the Body of Liberties. It banned slavery in many cases, but it allowed slaves to be held if they were prisoners of war, if they sold themselves into slavery or were bought somewhere else, or if they were sentenced to slavery as punishment by the government. The Body of Liberties used the word "strangers" to refer to people bought and sold as slaves; they were generally not English subjects. Colonists believed this term referred to Native Americans and Africans.