Although it would appear in studies of late antique ecclesiastical authority and power that scholars have covered everything, an important aspect of the urban bishop has long been neglected: his role as demonologist and exorcist. When the emperor Constantine made Christianity the official religion of the realm, bishops and priests everywhere struggled to "e;Christianize"e; the urban spaces still dominated by Greco-Roman monuments and festivals. During this period of upheaval, when congregants seemingly attended everything but their own "e;orthodox"e; church, many ecclesiastical leaders began simultaneously to promote aggressive and insidious depictions of the demonic. In City of Demons, Dayna S. Kalleres investigates this developing discourse and the church-sponsored rituals that went along with it, showing how shifting ecclesiastical demonologies and evolving practices of exorcism profoundly shaped Christian life in the fourth century.