This article explores the way slavery was defined under American law. The article begins with the colonial period, showing how Virginia law allowed for the treatment of slaves as property. The article then turns to the US Constitution, which refers to slaves as “persons,” but in some places also treats them as property. The article then turns to Supreme Court jurisprudence, showing how the Marshall and Taney Courts treated slaves mostly as property. Finally, the article considers how slaves were redefined as people through the Emancipation Proclamation, the enlistment of black troops, and the Thirteenth Amendment.