Pierrick Hildebrand demonstrates that the concept of a prelapsarian covenant, generally used as an argument for discontinuity between Zurich and Heidelberg, was clearly present in Zwingli and Bullinger. Further, Bullinger's covenantal terminology, which integrates the concept of the covenant with union with Christ, was adopted by Calvin and later by the Heidelberg theologians. Rejecting the idea that Zurich and Geneva represented two different traditions, Hildebrand details significant continuities and agreement while paying attention to differences. To do this, he draws on printed texts but also makes extensive use of previously unexamined manuscript sources, such as commentaries and sermon notes, to provide a much fuller account of the origins of Reformed covenantal theology. Working across a range of literary genres and with careful attention to historical contexts, this book presents the evolution of a crucial part of Reformation thought in a new light.