Heliopolis (the Greek name for the city), or iwnw (the ancient Egyptian name for the city), was the capital of the 13th nome (district) of ancient Egypt, dating back to the time of Narmer and the unification of Upper and Lower Egypt. The Egyptian name of the city, perhaps pronounced Aonu or Awenu, means “pillar.” This city name likely originated from the Egyptian creation epic stating that Heliopolis was the location of the original mound of creation which arose out of the primordial waters. In Hebrew, the Egyptian iwnw is spelled awn, and is a correct rendering of the ancient Egyptian name for the city. In English translations, the city is usually called On, which comes from the Septuagint (Greek) transliteration of the Hebrew. According to archaeological excavations, Heliopolis was occupied as far back as the Pre-Dynastic period, before ca. 3000 BC and the unification of Egypt. Excavations and ancient texts demonstrate that the city was important in the Old, Middle, and New Kingdoms, the Late Period, and the Hellenistic Period. During the Kingdom periods, Heliopolis was one of the largest cities in ancient Egypt and was a major center of worship for the gods Atum and Ra. Sun worship in this city is how it came to be known as Heliopolis (city of the sun).
At Heliopolis, the first evidence for occupation comes from the Pre-Dynastic period. Following that, the Old Kingdom Pharaohs Djoser of the 3rd Dynasty and Teti of the 6th Dynasty are attested by inscriptions from a chapel and an obelisk at the site. Tombs of the priests of Ra from the 6th Dynasty were also discovered in the temple precinct, indicating that sun worship at this city went back at least as far as the Old Kingdom. The next major Pharaoh attested comes from the Middle Kingdom in the 12th Dynasty. Senusret I ruled ca. 1971-1926 BC and built a temple to Re-Atum at Heliopolis, erecting twin red granite obelisks in commemoration of his Heb Sed festival. One of those obelisks still stands at the site today. The construction of this temple is also recorded on a roll of leather from the 18th Dynasty. Some construction from the time of Thutmose III, who ruled ca. 1504-1450 BC in the middle of the 18th Dynasty, was discovered at the site, and two obelisks that he erected there now reside in London and New York. A stele of Thutmose III found at Heliopolis records that “his majesty commanded to encircle this temple with a thick wall of stone-work.” Slightly later in the 18th Dynasty, Amenhotep III constructed a temple, according to architecture fragments discovered in the temple precinct of the city. Even Akenaten built at this site, and talatat (a special type of building block restricted to the reign of Akenaten) were discovered in the ruins of Heliopolis. Another stele from Heliopolis shows Akhenaten and his family worshipping the Aten, confirming that construction was carried out there specifically during his reign. A massive granite statue, thought to be of Ramses II, and a smaller statue bearing his cartouche were discovered in the area of a large limestone temple dated to his reign. A partial shrine of Seti I also demonstrates occupation and construction at the site during the 19th Dynasty. Temples dating to the 20th Dynasty and tombs dating to the 26th Dynasty have also been uncovered, and an obelisk from the 26th Dynasty king Psamtik II was originally discovered at Heliopolis. Even though ancient Heliopolis is buried underneath a modern suburb of Cairo, even the limited amount of finds demonstrate the city’s long and prominent history.
Joseph, who lived during the 2nd Intermediate Period, married the daughter of a priest of Heliopolis (Genesis 41:45). The priest whose daughter Joseph married was called Potipera—a name containing reference to the Egyptian sun god Ra. Since Heliopolis was the center for worship of the sun god, this name or title for a priest of Heliopolis containing the name of the sun god Ra is to be expected. The wife of Joseph, named as Asenath, may contain the name of the goddess Neith—a prominent goddess and mother of Ra who dates back to at least the 1st Dynasty, and whose center of worship was located in the Western Nile Delta region at Sais. As a patron deity in the Nile Delta who was closely associated with Ra, the name Asenath as a daughter of a priest of Ra at Heliopolis conforms to the likely possibilities.
According to the Masoretic text of Exodus 1:11, the Israelites built some type of storage or fortification at the cities of Ramses and Pithom (the meaning of the Hebrew word is not precisely known). However, the Septuagint Greek text adds that the Israelites also built at On, or Heliopolis. In the two Dead Sea Scrolls which contain this verse, one has a lacuna (missing section of text due to damage) at the end of the line following Ramses which could or would have contained the city Heliopolis, while the other scroll has an entire line missing which would best accommodate the longer Septuagint reading rather than only the names of Pithom and Ramses. Thus, it is very likely that the original text of Exodus 1 stated that the Israelites built at Ramses, Pithom, and Heliopolis. While all of these cities are in the Eastern Nile Delta region, Heliopolis is significantly farther south and may indicate that the Israelite work force was extended over a larger area of Egypt than just the Northeast Nile Delta region (cf. the Brooklyn Papyrus which may also indicate this). According to Exodus 1, all of this Israelite slave labor construction took place after the entire generation of Joseph and his brothers had died, their descendents had multiplied greatly, and then a new king arose over Egypt who did not know of Joseph (Exodus 1:6-11). This was likely after Ahmose I retook Lower Egypt in ca. 1570 BC, established the 18th Dynasty, and instituted a policy of slave labor for Asiatics in Egypt. It is known that at least one Pharaoh prior to the Exodus, Thutmose III, built extensively at Heliopolis. According to archaeological findings, Thutmose III built a massive stone temple with obelisks and a fortification wall, possibly in the fortress style of the Karnak Temple. This architectural style, or possibly storage facilities for the temples, could fulfill the description in Exodus 1:11. Pharaohs earlier in the 18th Dynasty may have had building done at Heliopolis, but currently there is no clear evidence for this. However, the construction ordered by Thutmose III at Heliopolis preceded the Exodus and fulfills the general requirements of Exodus 1. Thus, according to Exodus 1 the Israelites likely built at Heliopolis during the slavery in Egypt period, and the archaeological evidence clearly supports this possibility.