The way the concept of “communities” and “community” is deployed in scholarship hinders historical work on early Christianity, especially if early Christianity is to be treated as a normal human social phenomenon studied in the non-sectarian university. In contemporary English, “community” has a number of senses connected to uses developed in nineteenth and twentieth century Europe and North America. One sense of the word is territorial or features place as in “rural communities” and “flooding affected many households in the community.” A neighborhood in this sense can be called a community even if its inhabitants have almost no social interaction with one another. We also speak of a “linguistic community,” although there may be enormous cultural and political differences among those speakers. The range of meanings that has been important for scholarship on ancient Christianity, however, has a different history not only in Christian thought, but also in European and American social and political thought. This is the idea of community as a deep social and mental coherence, a commonality in mind and practice. Although Enlightenment traditions sometimes approached the idea, as in the French Revolution's fraternity in “liberty, equality and fraternity,” it has been the anti-Enlightenment and Romantic traditions that have featured community in this sense. Most famously, the sense was central to Fascism, National Socialism, many other twentieth century pre-World War Two conservative movements, and both Christian and non-Christian forms of communitarianism. A now much criticized, but influential, sociological approach to the concept is found in the work of Ferdinand Tönnies with his dualism between Gemeinschaft (community) and Gesellschaft (society), the former supposedly based upon the essential will (Wesenwille) of the participant. The idea of an essential and totalizing identity and commitment is very much like the idea of early Christian conversion. Factors within Christian traditions, together with broader European culture, have contributed to the pervasive appeal of communities and community, which have made the study of early Christian history oddly different from other ancient histories. The uses of the concepts in the study of early Christianity are far from descriptive and analytical.