The site had an Egyptian history before Hadrian founded his city. Remains of a temple built under Ramesses II establish a monumental presence long before the Roman period. The names and identification of earlier settlements in the area remain less secure than the temple itself. Hadrian's new foundation therefore occupied a landscape with an existing sacred past, rather than an empty tract beside the river. Across the Nile lay Hermopolis, an important Egyptian city whose proximity would shape the new settlement's regional setting.

The turning point came in October 130 CE, when Hadrian was travelling through Egypt and Antinous drowned in the Nile. Antinous came from Bithynia in Asia Minor and was closely associated with the emperor. The surviving accounts do not settle how he died. Cassius Dio reports that Hadrian described a fall into the river, while Dio himself favours a story of voluntary sacrifice. The later Historia Augusta also preserves competing explanations and describes the emperor's grief. These accounts are evidence for ancient interpretations, not proof that a particular rumour was true. His death and Hadrian's decision to commemorate him are much more securely attested than the circumstances of the drowning.

Antinous received divine honours, and in Egypt he was associated with Osiris, the god of the dead and renewed life. This identification gave his death a religious meaning within an Egyptian setting, while Hadrian's support helped establish a cult with a much wider reach. The ancient accounts connect the new city directly with Antinous and its name: Antinoopolis, the city of Antinous. The important distinction is between the historical establishment of worship and the religious belief that the dead young man now possessed divine power.

The city was organised as a Greek polis, with civic institutions and a planned urban landscape. Its streets followed a grid, and the remains and early surveys record colonnades, baths, a theatre, a gymnasium, an arch and facilities for public spectacle. Limestone construction and granite columns formed part of its monumental appearance. Privileges encouraged settlement, including arrangements that allowed its citizens to marry Egyptians without the normal loss of civic standing. Such measures connected the Greek citizen community with the surrounding population, although they did not erase every distinction between them. The city's river position and its connection with the Via Hadriana also gave it a role in movement, trade and administration. Hadrian's memorial therefore became a working city rather than simply a landscape of temples.

Festivals and images carried the cult beyond the city that bore Antinous's name. The Antinoeia combined commemoration with the competitive traditions of the Greek world. Elsewhere, worshippers represented Antinous through the forms and attributes of established deities, including Osiris and Dionysus. Pausanias describes his honours at Mantinea in Greece, where statues, a sanctuary and celebrations made his memory part of local religious life. These different settings should not be collapsed into one uniform empire-wide religion. What survives is nevertheless extensive enough to show the reach of the cult: a mortal associated with the imperial court became a recognisable sacred figure in communities far from the Nile.

Antinoopolis remained important after its founding generation and became a centre of Christian religious life in late antiquity. Palladius, who says he spent four years there, describes approximately 1,200 ascetic men around the city and discusses communities of women as well. His account is a witness to the religious landscape he encountered, not a modern census. The settlement's later history included political change, decline and the reuse of its buildings. Early European surveys recorded monuments that subsequent quarrying and lime-burning severely damaged, especially in the nineteenth century. Yet the archaeological site near modern Sheikh Ibada preserves more than a vanished city's name. Excavations have investigated streets, sacred buildings, burial grounds and other remains, allowing the history of its inhabitants to emerge beside the celebrated story of its foundation.