This book offers a fresh, original and interdisciplinary interpretation of what the Catholic Reformation meant at local diocesan level in the face of attempts by Rome to regularize worship c. 1550-1700. In the process of protecting the spiritual integrity of their patria, representatives of Italian local history such as Pietro Maria Campi of Piacenza (1569-1649)—who provides the focus of this wide-ranging study—significantly broadened the boundaries of historical study and helped to lay the foundations of Italian national history writing.