The Yedikule Dungeons constitute one of the oldest open-air museums in İstanbul and in Turkey. In reality, Yedikule had been constructed not to be used as a dungeon, but to welcome the kings and members of the foreign courts visiting the Byzantine Empire. According to research studies conducted by the Turkish Historical Society and according to available historical data, the Golden Gate was built by the Byzantine Emperor Theodosius as a triumphal arch. After Theodosius, his son came to the throne, and united a castle composed of four observation towers with the gate.