The work "Azerbaijan in the III-VII centuries" is devoted to an underdeveloped problem - the ethnocultural and socio-economic history of South Azerbaijan in the III-VII centuries. On the materials of ancient and early medieval sources, its geographical and strategic position, cities and population, administrative and social structure, slavery and forms of manumission, economy, Zoroastrianism and the temple of fire Ada urgushnasp, Christianity. The appendices provide a Russian translation from the Middle Persian inscription of the supreme Zoroastrian priest Kartir (III century), as well as the situation of Christians in Azerbaijan under the Sassanids, Arabs and Mongols, when the patriarch's residence was in the Azerbaijani city of Marag.