The word Ennead is derived from Greek meaning a collection or grouping of Nine things. In this
Case there are 9 deities:- Ra, Atum, Shu, Tefnut, Nut & Geb, Osiris, Isis, Set and Nephthys.
During the Armarna period [where the ‘heretic pharaoh’ Akhenaten moved the capital city from Thebes to Armarna and disolved the traditional gods in favour of the one god - [the Aten] Heliopolis was home to a temple called Wetjes Aten [Elevates the Aten]. Most of the monuments of the city were used to make different parts of Cairo over time and the materials used to construct Wetjes Aten are used in the gates to Cairo.