This study examines the terms and features in the Greek and Coptic documentary papyri from fourth-century CE Egypt which bear on the religious beliefs of their scribes, composers, senders, and recipients. These include onomastics, formulaic expressions, invocations of particular deities, the way the name of God is written, titles of officials, and linguistic choice. Where previous studies have often found predicative criteria and clear-cut boundaries, here a new narrative of the development of late-antique religious vocabulary and scribal practice is found in the ambiguity and the confluence of religious traditions which the papyri reveal.