Meymoun Qal’eh is the ruins of a castle located in the middle of Qazvin city, east of the Shazdeh Hossein Shrine. Some experts are of the opinion that the castle belonged to the Abbasid era and was constructed in 784 AD. Based on the artifacts unearthed at the site, others believe that it was built during the Buyid era (934–1062). The ruins suggest that the castle, which lies over a 5,000 square-meter area, had eight brick towers and functioned as a military fortress. According to archeologists, the castle had a basement that was used as a prison.