Babylon was a fortress city or castle in the Delta

Nile Delta

The Nile Delta is the delta formed in Northern Egypt where the Nile River spreads out and drains into the Mediterranean Sea. It is one of the world's largest river deltas—from Alexandria in the west to Port Said in the east, it covers some 240 km of Mediterranean coastline—and is a rich...

 of Egypt

Egypt

Egypt , officially the Arab Republic of Egypt, Arabic: , is a country mainly in North Africa, with the Sinai Peninsula forming a land bridge in Southwest Asia. Egypt is thus a transcontinental country, and a major power in Africa, the Mediterranean Basin, the Middle East and the Muslim world...

. It was situated in the Heliopolite Nome, upon the right (eastern) bank of the Nile

Nile

The Nile is a major north-flowing river in North Africa, generally regarded as the longest river in the world. It is long. It runs through the ten countries of Sudan, South Sudan, Burundi, Rwanda, Democratic Republic of the Congo, Tanzania, Kenya, Ethiopia, Uganda and Egypt.The Nile has two major...

, at latitude 30° N

30th parallel north

The 30th parallel north is a circle of latitude that is 30 degrees north of the Earth's equatorial plane. It stands one-third of the way between the equator and the North Pole and crosses Africa, Asia, the Pacific Ocean, North America and the Atlantic Ocean....

, and near the commencement of the Pharaonic Canal (also called Ptolemy's Canal and Trajan

Trajan

Trajan , was Roman Emperor from 98 to 117 AD. Born into a non-patrician family in the province of Hispania Baetica, in Spain Trajan rose to prominence during the reign of emperor Domitian. Serving as a legatus legionis in Hispania Tarraconensis, in Spain, in 89 Trajan supported the emperor against...

's Canal), from the Nile to the Red Sea

Red Sea

The Red Sea is a seawater inlet of the Indian Ocean, lying between Africa and Asia. The connection to the ocean is in the south through the Bab el Mandeb strait and the Gulf of Aden. In the north, there is the Sinai Peninsula, the Gulf of Aqaba, and the Gulf of Suez...

. It was the boundary town between Lower

Lower Egypt

Lower Egypt is the northern-most section of Egypt. It refers to the fertile Nile Delta region, which stretches from the area between El-Aiyat and Zawyet Dahshur, south of modern-day Cairo, and the Mediterranean Sea....

 and Middle Egypt

Middle Egypt

Middle Egypt is the section of land between Lower Egypt and Upper Egypt, stretching upstream from Asyut in the south to Memphis in the north. At the time, Ancient Egypt was divided into Lower and Upper Egypt, though Middle Egypt was technically a subdivision of Upper Egypt. It was not until the...

, where the river craft paid tolls when ascending or descending the Nile. Diodorus ascribes its erection to rebel Assyria

Assyria

Assyria was a Semitic Akkadian kingdom, extant as a nation state from the mid–23rd century BC to 608 BC centred on the Upper Tigris river, in northern Mesopotamia , that came to rule regional empires a number of times through history. It was named for its original capital, the ancient city of Assur...

n captives in the reign of Sesostris

Sesostris

Sesostris was the name of a legendary king of ancient Egypt who led a military expedition into parts of Europe, as related by Herodotus.-Account of Herodotus:...

, and Ctesias

Ctesias

Ctesias of Cnidus was a Greek physician and historian from Cnidus in Caria. Ctesias, who lived in the 5th century BC, was physician to Artaxerxes Mnemon, whom he accompanied in 401 BC on his expedition against his brother Cyrus the Younger....

 (Persica) dates it to the time of Semiramis

Semiramis

The real and historical Shammuramat , was the Assyrian queen of Shamshi-Adad V , King of Assyria and ruler of the Neo Assyrian Empire, and its regent for four years until her son Adad-nirari III came of age....

; but Josephus (l. c.), with greater probability, attributes its structure to some Babylonian followers of Cambyses

Cambyses

Cambyses can refer to two ancient rulers and two plays:-*Cambyses I, King of Anshan 600 to 559 BCE*Cambyses II, King of Persia 530 to 522 BCE*Cambyses, a tragedy by Thomas Preston...

, in 525 BC. In the age of Augustus

Augustus

Augustus ;23 September 63 BC – 19 August AD 14) is considered the first emperor of the Roman Empire, which he ruled alone from 27 BC until his death in 14 AD.The dates of his rule are contemporary dates; Augustus lived under two calendars, the Roman Republican until 45 BC, and the Julian...

 the 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

Legio XIII Gemina

Legio tertia decima Gemina was one of the most prominent Roman legions. It was one of Julius Caesar's key units in Gaul and in the civil war, and was the legion with which he famously crossed the Rubicon on January 10, 49 BC. The legion appears to have still been in existence in the fifth century...

. (It. Anton.

Antonine Itinerary

The Antonine Itinerary is a register of the stations and distances along the various roads of the Roman empire, containing directions how to get from one Roman settlement to another...

; Georg. Ravenn. etc.) Ruins of the town and fortress are still visible a little to the north of Fostat

Fostat

Fustat , was the first capital of Egypt under Arab rule...

 or Old Cairo, among which are vestiges of the Great Aqueduct mentioned by Strabo and the early Arabian topographers. (Champollion, l'Egypte, ii. p. 33.)