Arnold of Brescia (ca 1100-1155), exiled twice and finally martyred, takes us into the student world of Paris during the blossoming of the twelfth-century Renaissance, through an infamous heresy trial, to teaching in Paris, then Zurich, and into Rome where he was the spiritual leader of the city for almost a decade. Arnold believed the church should be separate from civil government. He supported the revived Roman Senate and the Roman people who were foremost among the many who loved and admired him. An Augustinian canon regular, Arnold made the authorities, ecclesiastical and imperial,...