French-born Protestant Reformer John Calvin led a sweeping reformation of law, politics, and society in sixteenth-century Geneva. Building on classical and earlier Christian sources, Calvin developed an innovative and integrative theory of rights and liberties, church and state, authority and power, natural law and positive law. Particularly striking was his use of the Decalogue as a source and summary of natural law, and as a template for spiritual and civil laws and rights in a Christian republic. Also novel was his theory of the uses of natural and positive law to cultivate a baseline civil morality and an aspirational spiritual morality in the community. Calvin and his followers saw law as a deterrent against sin, an inducement to grace, and a teacher of Christian virtue. They also believed in liberty, structuring their churches and states alike to minimize the sins of their rulers and to maximize the liberties of their subjects. Calvin distilled his legal teachings into sundry public, private, penal, and procedural laws for Geneva, and he broadcast them widely among other French and other European jurists, theologians, and political leaders of his day. Several of his basic teachings about law, politics, and society still live on today, both in secular legal thought and in modern Protestant churches.