Heliopolis , (Gr., city of the sun; called in old Egyptian On or An and Ha-Ra, in Hebrew Bethshemesh, and by the modern inhabitants Matariyeh), one of the most ancient cities of Egypt, below the S. E. point of the delta, on the E. side of the Pelusiac arm of the Nile, near the canal which connected that river with the Red sea, about 8 m. N. E. of the site of modern Cairo. From the remotest epoch it was renowned for its temples and priesthood. It was the chief seat of the Egyptian worship of the sun, and also of the sacred bull Mnevis; and the legends of the wonderful bird phoenix-centred about it. Its priests were the most [ learned in the land, and so important that they sent one third of all the deputies to the great council which assisted the Pharaohs in the administration of justice. Those belonging to each temple were organized among themselves with great exactness, and the office of the high priest, who was one of the first persons of the state, was hereditary. The Hebrew Joseph married Asenath, the daughter of one of these high priests.

To the Heliopolite priests resorted foreigners who wished to learn the wisdom of the Egyptians. Solon, Thales, Eudoxus, and Plato all studied under them; and when Strabo visited the place (24 B. C.) he was shown the halls which Plato was said to have occupied for 13 years. Alter being for ages a sort of university city, Heliopolis had much declined as early as the invasion of Cambyses (525 B. C), and was a city of ruins when visited by Strabo. Abdallatif, an Arab physician of the 12th century, described among its ruins colossal figures in stone, standing or sitting, and more than 30 cubits high. An obelisk of red granite, inscribed with the name of Osor-tasen I., whose date is fixed at about 3000 B. C, still remains, and is regarded as the most ancient known specimen of Egyptian sculpture; there are also some fragments of sphinxes and of a colossal statue which adorned the ancient temple of the sun. Near the hamlet of Matariyeh, which occupies a part of the site of Heliopolis, Kleber gained a victory over Turkish troops, March 20, 1800. (For Heliopolis in Syria, see Baalbek.)