Book excerpt: The Protestant and Catholic Reformations thrust the nature of conversion into the center of debate and politicking over religion as authorities and subjects imbued religious confession with novel meanings during the early modern era. The volume offers insights into the historicity of the very concept of “conversion.” One widely accepted modern notion of the phenomenon simply expresses denominational change. Yet this concept had no bearing at the outset of the Reformation. Instead, a variety of processes, such as the consolidation of territories along confessional lines, attempts to ensure civic concord, and diplomatic quarrels helped to usher in new ideas about the nature of religious boundaries and, therefore, conversion. However conceptualized, religious change— conversion—had deep social and political implications for early modern German states and societies.