Ctesiphon

Ctesiphon, the imperial capital of the Persian Parthian Arsacids, and of the Persian Sassanids, was one of the great cities of ancient Mesopotamia.

The ruins of the city are located on the east bank of the Tigris, across the river from the Hellenistic city of Seleucia. Today, the remains of the city lies in Baghdad Governorate, Iraq, approximately 35 km south of the city of Baghdad.

Ctesiphon in "The Banner of Kaviyan"
Ctesiphon was the Persian Imperial Capital but the King of Kings Khusro feared to enter it since it was prophesized that he would be destroyed if he did so. He did send the Banner of Kaviyan there for safe-keeping having it hidden in the Imperial Palace. With the Romans reversing his previous successes, he was forced to enter the city to retrieve the banner since it would grant invincibility to an army flying it but was unable to find it. Khusro fled empty-handed and was eventually captured by his son and killed by slow torture thus fulfilling the prophesy.