It is the only Byzantine Palace still standing in the world. It is not known exactly by whom and when the palace was built. The structure was called the Palace of Constantine (Palatium Constantini) by Europeans in the 16th century, and later the Palace of Porfirogenetos.In the conquest of Istanbul. it went down in history as the first imperial building taken by the detachments entering the city during the conquest. The palace was repaired and used for various purposes in later periods.fell into ruin again in the 17th century. Some parts of it were used as elephant stables and zoos.