Cairo (Arabic: القاهرة, Romanized: al-Qāhirah,) is the capital of Egypt and the city-state Cairo Governorate home to 10 million people. It is also part of the Largest urban agglomeration in Africa, the Arab world and the Middle East. The Greater Cairo metropolitan area, with a population of 21.9 million, is the 12th Largest in the world by population. Located near the Nile Delta, the city first developed as Fustat, a settlement founded after the Muslim conquest of Egypt in 641 next to an existing ancient Roman fortress, Babylon.
It later superseded Fustat as the main urban centre during the Ayyubid and Mamluk periods (12th–16th centuries). Cairo has long been a centre of the region’s political and cultural life, and is titled “the city of a thousand minarets” for its preponderance of Islamic architecture. Cairo is a World City with a “Beta +” classification according to GaWC.
It has the oldest and largest film and music industry in the Arab world. As well as the world’s second-oldest institution of higher learning, Al Azhar University. Many international media, businesses, and organizations have regional headquarters in the city. The Arab League has had its headquarters in Cairo for most of its existence.
The area around present-day Cairo had long been a focal point of Ancient Egypt due to its strategic location. At the junction of the Nile Valley and the Nile Delta regions (roughly Upper Egypt and Lower Egypt). Which also placed it at the crossing of major routes between North Africa and the Levant. Memphis, the capital of Egypt during the Old Kingdom and a major city up until the Ptolemiac Period, was located a short distance south west of present-day Cairo. Heliopolis, another important city and major religious center, was located in what are now the modern districts of Matariya and Ain Shams in northeastern Cairo. It was largely destroyed by the Persian invasions in 525 BC and 343 BC and partly abandoned by the late first century BC.
However, the origins of modern Cairo belongs back to a series of settlements in the first millennium AD. Around the turn of the fourth century, as Memphis was continuing to decline in importance, the Romans established a large fortress along the east bank of the Nile. The Roman emperor Diocletian built the fortress, Babylon, by the (r. 285–305) at the entrance of a canal.Connecting the Nile to the Red Sea that the emperor Trajan created earlier by(r. 98–115). Further north of the fortress, near the present-day district of al Azbakiya, was a port and fortified outpost known as Tendunyas (Coptic: ϯⲁⲛⲧⲱⲛⲓⲁⲥ) or Umm Dunayn. The city was important enough that its Bishop, Cyrus, participated in the Second Council of Ephesus in 449.