the role of the hyrcania’s fortresses in the struggles on the easter sasanian boarders

hyrcania (gorgan) has long attracted men of power due to its strategic and economic location. according to historical evidence, the iranian governments before the sassanid dynasty, attempted to dominate the region in order to consolidate their power. the sassanid dynasty, following the same policy of the former dynasties, not only established an important military base there but also constructed strong defensive walls and intricate and well-equipped fortifications in the region. based on the related historical texts and the relevant archaeological findings, we have demonstrated that the construction of defensive gorgan wall with its special fortifications not only prevented attackers from entering into the iranian territory but also led to the prosperity of gorgan state that was responsible to endure the security in the area. with the construction of this defensive wall, hyrcania was considered as an important sasanian base in the eastern territories. it will be argued that the construction of the defensive wall shows that it was not built merely as an emergency plan, but it was part of a well-calculated and complex plan of the sassanian empire and provided maximum protection for gorgan in the 5th century ad.