The importance of the early Christian letter can only be understood in the context of information exchange in the early Christian church. The information exchange networks that characterised first-century Jewish letter-writers were spatially very limited when compared with the expanded remit of letter-writing Christian leaders. This chapter deals with the networks of communication reflected in the late-antique Christian letter, a period when there was a significant increase in long-distance travel as elites established communication networks that went beyond single provinces. One of the greatest innovations of the Christian letter was that it could be addressed to people whom one did not already know. Previously, elite correspondence was carried out with known people who were absent, and thus letters provide our best look at how such people communicated.