Hisar Kapia (Castle Gate), Plovdiv

The Castle Gate in Plovdiv, situated around the eastern gate of the Acropolis fortress wall, stands as one of Plovdiv's iconic symbols. The origins of Castle Gate date back to ancient times when there was a gate in this location. Beneath the modern-day cobblestone street pavement, one can find the foundations that date back to the Roman period, likely originating in the 2nd century AD.

However, the most prominent features of Castle Gate owe their current appearance to medieval alterations, particularly those from the 11th to the 13th century. Above the outer arch, one can observe distinctive construction techniques, wherein each stone is encased in pieces of red brick, bonded together with plaster. This method is characteristic of the masterful craftsmanship of Bulgarian builders during the period of the Second Bulgarian Empire.

Adjacent to Castle Gate stands the outdoor quadrangular tower, situated under the altar of the Saint Konstantin and Elena Church. This tower, with its crypt-like function as an ossuary, has been an integral part of the ensemble for many years. Further south from the church complex, one can observe a substantial section of the fortified wall, which dates back to the 5th to 6th century during the reign of Justinian the Great.

With the Ottoman invasion in the 14th century, a Turkish garrison was established here, causing the Castle Gate's significance as part of the Acropolis' fortification system to wane. In later centuries, particularly during the 17th and 18th centuries, the area saw the construction of houses belonging to the wealthy merchant class. These Revival Period houses were built into the walls of the former fortress, further enhancing the unique character of the Castle Gate.