The famous fortress in Istanbul, built by Mehmed the Conqueror in 1458, shortly after the capture of Constantinople, by adding three more massive towers to the four ancient towers of the Theodosian walls at the Golden Gate of the city.
In the fortress, the Sultan kept his treasury and archives. Political opponents of the sultan were also kept here, including ambassadors of the powers that fought with him (for example, P. A. Tolstoy and Ya. I. Bulgakov). Some of them (Napoleonic emissary Francois Pukvil, 1799-1801) felt very at ease in the fortress, indulged in literary creativity and were in constant correspondence with their government. At the same time, many disgraced viziers were executed in Yedikul, the last emperor of Trebizond and the Wallachian ruler Konstantin Brynkovyanu.
The courtyard of the fortress was enlivened by a miniature mosque with a fountain. In the 1830s, Yedikule ceased to be used as a prison, the barracks were demolished, and a school was built in their place. In 1895 the Seven-Tower Castle was declared a museum.