Iunu

Iunu, also written On, was the ancient Egyptian city that later gave its Greek name Heliopolis, meaning City of the Sun. It occupied a religious center on the eastern bank of the Nile in the area of what is now the greater Cairo region, and it was the site of a major temple complex dedicated to Ra, the sun god.

Historically, Iunu emerged as a leading religious and ceremonial center from the early dynastic period and remained influential into the late antique era. The city’s main temple complex, the sun temple of Ra, housed solar cults and priestly hierarchies. Heliopolitan theology emphasized a primordial creation narrative and an Ennead of deities associated with the sun’s order, which influenced both Egyptian religion and neighboring cultures.

In the Greco-Roman period, Iunu continued to function as a pilgrimage and religious hub, though political power shifted elsewhere. Archaeological remains from the site include temple precincts, pylons, and monumental obelisks. Some obelisks associated with Heliopolis were relocated in antiquity to other cities, contributing to their appearance in places far from their origin, such as the monuments now seen in European and American cities.

Today, the site is part of the broader Cairo area and is associated with the modern district of Heliopolis, which preserves the historical memory of the ancient city. Iunu is significant in studies of ancient Egyptian religion as the principal center of Ra worship and as a locus for solar theology and the development of early Egyptian cosmology.