Heliopolis - city of the Sun
One of the three major cities of ancient Egypt, after Thebes and Memphis, was Heliopolis, “city of the sun” in Greek, was situated in the area of Tell Hisn on the northwestern outskirts of modern Cairo. The ancient Egyptian name was Iunu, or iwnw, meaning pillar. Today it is largely covered by the suburbs of Cairo at el-Matariya and Tell Hisn. It is not situated on the bank of the Nile, but lay inland, to the west of the river, and was connected thereto by an ancient canal. In biblical Hebrew Heliopolis was referred to as, Ôn ( אן ) or Āwen.
Heliopolis was the capital of the 13th Lower Egyptian nome. By the time of the Old Kingdom, the city was a centre of astronomy as reflected in the title of its high priest, “Chief of Observers” or “Greatest of Seers”. The Priests of Heliopolis were also responsible for the Calendars and therefore the “Keepers of Time“.This title was held by Imhotep during the 3rd Dynasty reign of King Djoser Netjerikhet, and dates earlier to the reign of Khasekhemwy in the 2nd Dynasty.
Heliopolis also had a reputation for learning and theological speculation, which it retained into Graeco-Roman times when Heliopolis flourished as a seat of learning; the schools of philosophy and astronomy are claimed to have been frequented by Orpheus, Homer, Pythagoras, Plato, Solon, and other Greek philosophers. Much of that learning centred on the role of the sun in creation and maintenance of the world and in the persons of the gods Atum ("the evening sun") and Re-Horakhty (literally Ra, [who is] Horus of the Two Horizons).
One of the earliest, richest and most influential of theological traditions, centred in Heliopolis was summarised in the concept of the Ennead, the group of nine gods that embodied the creative source and chief forces of the universe. By the beginning of the Old Kingdom that system had been formulated into a coherent philosophy and it dominated Egyptian thought for the next three thousand years.
Pyramid Text Utterance 600 records this theology: “Atum-Kheprer, you have come to be high on the hill, you have arisen on the Benben stone in the mansion of the Benu-bird in Heliopolis, you spat out Shu, you expectorated Tefnut, and you put your two arms around them as the arms of a ka-symbol, so that your ka might be in them. O great Ennead which is in Heliopolis: Atum, Shu, Tefnut, Geb, Nut, Osiris, Isis, Set, Nephthys—-children of Atum, extend his heart to his child, the king, in your name of Nine Bows.”
In the time of the major prophets, Isaiah made a reference to the City of the Sun as one of the five cities of Egypt that would come to speak Hebrew. However he made a wordplay on “city of the sun” (’ir hašemeš) by writing ’ir haheres which literally means “city of destruction”. These play of words were a prophetic description later reinforced by both Jeremiah and Ezekiel.