This volume brings theoretical and methodological discussions from religious studies, ancient history, and classics to the study of ancient religions, thus attempting to bridge a disciplinary chasm often apparent in the study of religions in antiquity. It examines theoretical discourses on the specificity, origin, and function of 'religion' in antiquity, broadly defined here as the period from the 6th century BCE to the 4th century CE. In addition, it explores the crucial question of what is meant by the term 'religion' and its applicability when employed to describe traditions that antedate the historical periods known as the Enlightenment and the Reformation. Theorizing about religion is often seen as an accomplishment of modernity, neglecting the insights stemming from the 'pre-modern' period. The contributors to this volume offer detailed discussions and links between how the ancients theorized about their religions and how modern scholars discuss about such discourses in their academic environments.