The effect of location and structure of border cities on the sense of territoriality of governments (Case study: Nasibin city in the Sassanid period)

Following the gradual extinction of the Seleucid dynasty, whose territory was weakened by the Parthian powers in the east and the Romans in the west; The Parthians bordered the Romans. The common borders of the two powers led to conflicts between them; Due to the internal problems of the Parthians, the Romans were able to gain access to geopolitical regions such as Mesopotamia. After the extinction of the Parthians, their territory was transferred to the Sassanids along with the death of their conflict with Rome. The results of the research indicate that the city of Nasibin was one of the main centers of the Iran-Rome wars in the Sassanid period; As the access to it was considered to be in the possession of Mesopotamia and Asia Minor, and on the other hand, Nasibin was located on the border of Iran and Byzantium and was considered as one of the places where the transit of goods took place. Therefore, both Iran and Byzantium did not want to lose control of the city politically, economically, or even religiously. Therefore, the loss of such a city was considered as a major change in the balance of power in the Miyanrodan, As Iran and Byzantium were not willing to lose this city, and because of this, there were continuous conflicts between them, which gradually led to the weakening of the power of the two empires.