This study describes power and politics in Rome and the role of the papacy in European politics during the sixteenth and seventeenth centuries. It attempts to overcome the traditional historiographical approach to the role of the papacy during this period by focusing on the actual mechanisms of power in the papal court—political, personal, spiritual, and ceremonial. Based on new research in Italian and other European archives, it charts the transition from a political to a primarily spiritual power between the Renaissance and the Peace of Westphalia.