The Hippodrome served as an ancient racetrack where ancient chariot races, athletic competitions were held, and was centrally decorated with the Egyptian Obelisk and other famous columns. Its construction began in 203 by the Emperor Septimus Severus and it was subsequently enlarged by Constantine the Great. According to one estimation, it had a capacity of 100.000 people. After the Nika riots in 532, the chariot races lost their importance and in 1204, during the fourth crusade, it was greatly damaged. After the conquest of the city by the Ottoman Turks in 1453, the area served as one for horse trading. For that reason, the area is named At Meydani (horse square) today.