The significance of faith as a cohesive element in the development of commercial networks in the Indian Ocean is well documented in the case of Islamic and Jewish diasporas of the medieval period, but what was the situation in Late Antiquity, when Christianity was the expanding religion in the areas east and south of the Mediterranean? Drawing on late Roman literary sources and the concept of the “trading diaspora,” this study emphasizes the interaction among trade, religion, and politics in the area of the Indian Ocean, arguing that Christianity had the potential to play a role resembling that of Judaism and Islam in later periods: Christians also were active as traders and travelers in the monsoon commerce. Fellow Christians came together for worship, company, and security, and Christian rulers involved themselves politically and militarily in order to secure the safety and interest of their coreligionists.