Anatolian Fortress is a castle built by I.Beyazýd, at the narrowest point of the Bosphorus and on the Anatolian side of Bosphorus. It is also known as Yenihisar, Güzelcehisar and Güzelhisar. The sources show different years such as 1390, 1391 and 1395 as the date of construction.
It consists of an inner fortress and an outer fortress wall. This interior castle is also important because it is the oldest Ottoman building in Istanbul. The goal of construction the fortress was to block possible military support from the Black Sea to Istanbul and to supervise maritime traffic in the Bosphorus.
After the conquest of Istanbul, Anatolian Fortress lost its military importance.