It may be surprising for many to hear that a Reformation occurred in Italy. We normally use the term “Reformation” to describe the defection of Protestants from Roman obedience in places like Wittenberg, Strasbourg, Zurich, and Geneva. But surely the Italian peninsula was always loyal to the papacy? Yet Italy was also poised for gospel renewal in the opening decades of the 16th century. Waves of invasions by French and Habsburg armies, epidemic diseases such as syphilis, harvest failures, and a growing resentment toward clerical authority produced a generation of troubled hearts. And, as they did else elsewhere, reformers in...