Due to their longevity of castles, utilize and importance in various governments, castles are among the most essential data that are discussed in archeology. Until now, many ancient castles have been identified within the vast Parthian and Sasanian territories inside and outside of Iran. The abundance of these structures in the mentioned periods, in addition to the protection and regional political aspects, due to the protection of various communication routes such as the Silk Road and the side routes of this road, was also important to the development of trade in the ancient world. As one of the eastern plains of Central Zagros, Azna is considered one of the crucial archaeological areas, which is located on the east-west and north-south communication route of ancient civilizations. Despite the registration and identification of a large number of ancient sites in the Parthian and Sasanian periods in the Azna plain, no targeted research has been done on these works and the settlements of the mentioned periods in Azna are unknown. "Qela Dez" castle which is located on the top of a huge stone mountain overlooking Azna plain, in the east of Masoud Abad village.
During the archaeological researches of this castle, which was conducted by the authors in 2019, many ancient finds were identified and documented, including architectural remains, pottery and bone data. The main goal of this research is to investigate the architectural features, periods of settlement and the role of this castle in the regional and extra-regional trade network. based on the remains of this fort, it can be acknowledged that its residents have a complete knowledge of the region's ecology and the use of local materials with a combination of rock carving and stone materials, mortar and square-shaped bricks, an iconic, big and impassable structure. created in due to achieve