Theodosius I made the opening of the square in 393. There were structures such as a basilica, a church; a bath etc. and a statue of Theodosius riding a horse as well as other sculptures were adorning the square. Metallic sculptures had been removed during the Latin invasion.
First palace of the Ottomans was built in the field of the university in 1454, them it moved to Topkapi Palace. Beyazıt Külliye was also built near the palace in Bayezid II (1481-1512) era. Beyazit Mosque as the most magnificent structure of the square has an importance for representing the early period of characteristic of classical Ottoman architecture. Beside this mosque, there is the big gate of the university, madrasah building as a part of külliye and Beyazit Library in the square.
After the collapse of the front facade of Şimşekhane building during the repairmen of Ordu Street revealed some remnants. Those remnants belong to a triumphal arch and it was the monumental entrance of the square. Some parts of the remnants can be seen in the Archaeological Museum, and the rest remains in its original place.