This is an interdisciplinary study spanning theology and canon law that leads the reader to the struggles of the fourth century. Stephens challenges the older interpretation of the years after the death of Constantine (337) that understood the mid-fourth century as a period defined by bitter theological quarrels (between Nicenes and non-Nicenes, Arians, etc.) and the quest for the right Creed. Stephens aims to bring the (political and legal) role of bishops back to centre stage and consequently focuses on more institutional aspects of the fourth century. According to him, the role of councils and of the bishop of Rome was crucial in this formative period for the institutions of the Church; furthermore, ecclesiastical leaders needed to answer the question of how to deal with bishops who were exiled under Constantine. To this end, Stephens reconsiders the canons of the Council of Antioch (341) and of Serdica (343?) to learn more about episcopal power in the mid-fourth century. This study is intriguing because it demonstrates how important normative texts are to the historian for reconstructing institutional settings and historical developments in order to understand theological and philosophical discussions. Canon law texts as historical source material have long been underestimated by other disciplines, as the author correctly observes. Stephens's more general reflections on canon law and its nature (pp. 171–215) highlight some interesting aspects of early canon law, for instance its character as guidelines rather than as strict rules, its complexity, and also the lack of means to enforce it.