The period 300-600 AD saw huge changes: the Graeco-Roman city-state was first transformed then eclipsed; much of the Roman Empire broke up and was reconfigured; new barbarian kingdoms emerged in the Roman West. Above all, religious culture moved from polytheistic to monotheistic. Here, 20 papers by international scholars explore how group identities were established against the shifting background. Separate sections treat the Latin-speaking West, the Greek East, and the age of Justinian. Themes include religious conversion, Roman law in the barbarian West, problems of Jewish identity, and what in Late Antiquity it meant to be Roman.