Hieraconpolis or Nekhen was the religious and political capital of Upper Egypt at the end of the Predynastic period (c 3200-3100 BC).
The foundation, circa 3100 B.C., of a united kingdom of Upper and Lower Egypt was achieved by empire-builders from the extreme south of the Egyptiac World of the day, in the neighbourhood of the modern Al-Kāb, [footnote] between Thebes and the First Cataract.
The nucleus of the “nome” (canton) which was the original domain of these Horus-worshipping empire-builders consisted of a pair of cities facing one another across the Nile: Necheb (Graecè “Eileithuia”) on the site of the modern Al-Kāb on the east bank of the Nile, and Nechen (Graecè “Hieracônpolis”, in allusion to the hawk (“hierax”) which was both the heraldic emblem of the city and the symbol of its god (Horus) on the west bank. (See Hall, H. R.: The Ancient History of the Near East (London 1911, Methuen), pp. 93-94; Meyer, E.: Geschichte des Altertums, vol. 1, Part II, 3rd ed. (Stuttgart and Berlin 1913, Cotta), pp. 80 and 111).
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The political union, from this base of operations, of the whole of the Lower Nile Basin between the First Cataract and the Mediterranean was immediately followed by a northward shift of the seat of power. The Hieraconpolite empire-builders established their imperial residence at Thinis, and their necropolis at Abydos on the opposite bank of the Nile, down-stream from their ancestral canton; and the de facto centre of imperial administration seems soon to have moved on still farther down-stream to Memphis. Thereafter, this ideally convenient site, at the point of junction between the mouth of the Nile Valley and the head of the Delta, remained the seat of government of the Old Kingdom to the end. The de facto capital of its spring-time became the de jure capital of its summer, when the Thinites were followed by the pyramid-builders of the Third and Fourth Dynasties; and, when [the Old Kingdom’s] summer passed over into autumn, Memphis was still the place from which the demonic pyramid-builders’ pious Heliopolitan successors attempted to exert their gradually diminishing authority.
Heliopolis was important during the Fifth Dynasty (c 2465-c 2325 BC), when the worship of Re became the state cult.
A Study of History, Vol VII, OUP, 1954