Yedikule, the "Fortress of the Seven Towers", is built on to the southern section of the Theodosian Walls. Its seven towers are connected by thick walls to make a five-sided fortification. One of the sides, with four towers spaced along it, is formed by a stretch of the land walls themselves.
The fortress as it is today incorporates both Byzantine and Ottoman features. The two stout, square marble towers built into the land walls once flanked the Golden Gate (now blocked up), the triumphal entrance into medieval Byzantium built by Theodosius II. Imperial processions would enter the city through this gate to mark the investiture of a new emperor or in celebration of a successful military campaign. When it was first built, the gate was covered in gold plate and the facade decorated with sculptures, including a statue of a winged Victory, four bronze elephants and an image of Emperor Theodosius himself.
In the 15th century, Mehmet the Conqueror added the three tall, round towers that are not part of the land walls, and the connecting curtain walls, to complete the fortress.
After viewing the castle from the outside, you can enter through a doorway in the northeastern wall. The tower immediately to your left as you enter is known as the vazıh kule, "the tower with inscriptions". This was used as a prison for foreign envoys and others who fell foul of the sultan. These hapless individuals carved their names, dates and other details on the walls and some of these inscriptions are still visible.
Executions were carried out in Yedikule Castle, in the northern of the two towers flanking the Golden Gate. Among those executed here was the 17-year-old Osman II - In 1622 he was dragged to Yedikule by his own Janissaries . after four years of misrule, which included, it is alleged, using his own pages as targets for archery practice.
The walkway around the ramparts is accessible via a steep flight of stone steps. It offers good views of the land walls and nearby suburbs, and also of the cemeteries. (s1)