Fortress of Babylon was a citadel built by the Romans and its origin is disputed by Coptic historians. Some date its origin to the nineteenth century B.C, after Pharaoh Sesostris defeated the Babylonians and took the prisoners of Egypt as slaves. The prisoners rebelled, building a fortress around their home which became known as Babylon. Others believe the fortress was built in the late sixteenth century B.C. by Nebuchadnezzar, king of Babylon, after conquering Egypt.