Combining classical, epigraphical, and biblical sources with social-scientific methodology, this monograph questions the way in which modern scholarship has tended to discuss ancient conversion. The author challenges long-held assumptions of psychological continuity between ancient and modern people, and offers in place of these assumptions a model founded on the categories the ancients used themselves. Graeco-Roman and Mediterranean religions and philosophies, including Hellenistic Judaism and Christianity, framed their religion in the language of patronage / benefaction and loyalty, and thus an understanding of ancient conversion must start there.