Babylon Fortress, also known as the "Candles Palace", is an ancient Roman fortress built around 30 BC during the reign of Emperor Augustus in Egypt.
The fortress is situated on the eastern bank of the Nile Delta in the area known today as Old Egypt. The site featured the Hanging Church, the Coptic Museum, and the Roman Orthodox Church of St. Georges (the Melkites).
Babylon Fortress was built at the boundary between Lower and Middle Egypt, where rivercraft paid tolls when ascending or descending the Nile.
According to Diodorus, the first fort was built by rebel Assyrian captives during the reign of Sesostris, while Ctesias dated it to the time of Semiramis. However, with greater probability, Josephus attributed its construction to some Babylonian followers of Cambyses in 525 BC. The Romans later built a new fortress closer to the river, using typically Roman red and white banded masonry.
During the time of Augustus, Deltaic Babylon became a town of some importance and was the headquarters of the three legions, which ensured the obedience of Egypt. In the Notitia Imperii, Babylon is mentioned as the quarters of Legio XIII Gemina.
Ruins of the town and fortress are still visible a little to the north of Fostat or Old Cairo, among which are vestiges of the Great Aqueduct mentioned by Strabo and the early Arabian topographers.
In December 640, during the Arab conquest of Egypt, the Byzantine fortress held out for about seven months before finally falling to the Arab general Amr Ibn Al-'As.