Late antiquity
Late antiquity is a period of Eurasian, Mediterranean, and Near Eastern history conventionally placed between the later third century and the eighth century CE. It describes the transformation of the world from classical antiquity after the crisis of the third century of the Roman Empire, the reorganization of Roman imperial government under Diocletian and Constantine, the rise of the Sasanian Empire to the Roman East, the formation of post-Roman kingdoms in the western provinces, the spread of Christianity and the institutionalization of rabbinic Judaism, and the emergence of Islam and the early caliphates. Late antiquity, therefore, is an era of overlapping and interconnected regional transformations taking place at different speeds, and it includes the erosion of some ancient institutions and the beginning of medieval ones.