Daily News Egypt carried a brief article about the Roman ruins in Old Cairo here. The article says,
The fort was built on the southern end of the old Pharaonic town Per-Hapi-On, or ‘The river house of On’. According to some historians the mispronunciation of the name by the Romans led to the name Fort Babylon but others claim it was named after a number of captives brought there from Babylonia during the time of Sesostris.
Roman Emperor Diocletian built the fort in 300 C.E. as the stronghold of three legions in charge of securing Egypt. The garrison of Fort Babylon vowed to secure ships on the Nile and a canal that passed through the town connecting the Nile with the Red Sea. This canal was first established by the Pharaohs, and was restored and enlarged by the Roman Emperor Trajan. The fort was renovated and fortified by the Roman Emperor Arcadius.
Our photo shows ruins of the Roman fort that was known as Fort Babylon in Roman times. At that time the Nile River flowed beside the Fort, but has since changed its course. New building of Old Cairo dwarf the old structure.
The sign in front of the structure says that it was constructed by Diocletian (c. A.D. 300) to fortify the Roman harbor of Old Cairo built by Trajan (c. A.D. 110).
HT: Agade List