In his recent study, The Gnostics, David Brakke encourages greater attention to "real social and religious distinctions among ancient Christians" (15). What can we discern about social arrangements and interactions among Christians beyond the level of discourse? Focusing on second- and early third-century Alexandria, this paper extends the efforts of Brakke and others by reconstructing likely facets of the social contexts in which ancient Christians developed and debated their diverse perspectives and practices. In this paper, I am especially interested in closely connected texts and traditions, emerging in or near Alexandria, that both highlight gnosis as a key aspect of Christian social identity and offer glimpses of intra-Christian interactions, including disputes; these sources of evidence include the writings of Clement of Alexandria and Testimony of Truth (NHC IX,3). My attention to social setting is further informed by the interests and practices of ancient philosophical schools as well as by the Alexandrian intellectual milieu. I also examine evidence of ancient Christian rituals as significant for social identity. To conclude, I consider how firmer boundaries among Christian groups evolved over time, with attention to divergent perspectives on martyrdom as one likely factor. My paper thus illuminates certain complex social dynamics behind the differences that are more simply cast as "orthodoxy" and "heresy" in ancient Christian discourse.