Set against the backdrop of one of the most tumultuous periods in Roman history, The Tetrarchy and Diocletian's Great Persecution offers an authoritative and deeply researched account of the empire's radical political restructuring and its devastating campaign against early Christians. Philip Davies explores how Diocletian's creation of the Tetrarchy—a novel system dividing imperial power among four rulers—sought to restore order to a fractured empire, while simultaneously enforcing religious uniformity through the harshest persecution Christianity had yet endured.

Drawing on a wealth of primary sources and modern scholarship, the book reveals the complex motivations behind the persecution, the key roles played by figures like Galerius, and the paradoxical effect of repression in strengthening Christian identity and cohesion. Davies traces the gradual decline of persecution, culminating in Constantine's groundbreaking Edict of Milan and the transformation of Christianity from a persecuted sect to an imperial religion.

Through incisive analysis, the book illuminates the enduring legacy of Diocletian's reforms and persecutions in shaping the political theology of late antiquity, the rise of Christian imperial power, and the profound shifts that marked the twilight of the Roman pagan world. Essential reading for scholars and general readers alike, this volume sheds new light on a pivotal era that forged the foundations of the medieval Christian empire.