The western land walls strecthing from the Golden Horn to the Sea of Marmara were constructed during the reign of the Theodosius II in the 5th century A.D. The sea walls measure 16 km, and; the land portion of the walls, 6 km. The larger section of the land walls has a triple defense system: first a moat, than a lower wall with 108 towers, and, farthest inside, a higher main wall with 96 towers. This beautiful exemple of classical Roman style construction has white stones with layers of brick. Beyond the Topkapi district walls the new park and exhibits of Conquest of Istanbul gallery opened at 2009. A 9 th century portion of the walls stretches from the Golden Horn to the hill.
Many original gates have survived to the present. The walls have been partially restored with asistance from the Istanbul Municipality and UNESCO. Close the Marmara shore is the Roman-era Golden Gate with two monumental towers. The first construction completed after the Turkish conquest of the city was tha addition of five towers to the Golden Gate.
Yedikule is important because of the area it occupies and the historical events that took place here. This fort served as an indispensable strongehold not olny for Byzantium, but also for the Ottoman Empire and afterwards. The Golden Gate, the main state entrance into the capital which was used for triumphal returns by victorious emperors from battle, is located here. The gate is extremely high and glorious. Inside, there is a relief of the two-headed Byzantine eagle. The gate was built by Theodosius I.
During the Ottoman era, this location served as the treasury for some time, but later the treasury was relocated in the palace for security reasons. The original singel tower that existed during the Byzantine era was joined by six more towers in the Ottoman Era. Later, this fort was used as a dungeon. Political criminals, including very famous politicians, were held in the cells, which can still be visited, and executed here. A famous historical figure who was executed here was Sultan Osman II (Young Osman), who was killed by rebels. Also foreign messenger or spies were held here. The writings on the walls left from this period can still be read. Today, the whole district is named after the towers, which are used as a museum.