Once a famous citadel and strategic stronghold, this fort has been built on a huge rock and covers an area of six square kilometers in all. It is 300 meters long and 200 meters wide and consists of two parts.

The fort is a five-story structure of unbaked brick and must have been constructed before the fifth and sixth centuries A.H. (11th and 12th centuries A.D.).

The place has undergone frequent repairs and comprises a rampart, an ancient entrance, adequate fortifications, some Safavid structures, a mosque, and a building known as (Char-Fasl) or (Palace of four seasons).

There are two inscriptions in this vast and magnificent construction, which are indicative of recent reparations. Both tablets bear the date 20th Azar 1337 S.H. year (1958 A.D.); one of these has been installed by the society for the Preservation of National Monuments and the other, by the Department of Archaeology.

The next of the latter is as follows: (The Citadel of Bam, which was habitable and in a fairly good condition until a hundred and fifty years ago, has, according to (Hundud al-Alam) and other reliable sources that have come down to us from 4th century A.H. (10th century A.D.), been founded some 2000 years back, and has been repeatedly repaired thereafter.

This is one of the most splendid historical sites in the whole world: while most of the best known historical sites in the world, like Fars (Persepolis, Athen`s Acropolis, Rome`s forum and Coliseum, Paris` Versailles,... signify a limited period in history, Arg-e-Rayen displays the imprints of 2000 continuous years of a dramatic, eventful history from its foundation, presumably during the Parathion period (250 BC - 224 AC), up until about 150 years ago when in the reign of Nasser-a-Din Shah Qajar (1831-1896, king 1548-1896) the ancient town was gradually deserted. This peculiarity has made estimation of the precise age of most parts of this historical complex rather difficult, sometimes even impossible.

The legends have it that the city was founded by Bahman, the son of Esfandiar, one of the legendary kings in the Esfahnameh, corresponded to Ardashir the Long Armed (Artaxerexes Longimanus, 429 BC, king 464-424) son of Xerexes I, the Achamenide King-of-Kings. However, most of the historians refer to the story of (Haftvad) in the Shahnameh, or (Haptanbad) in the Karnamak-e-Ardashir-e-Papkan, a historically true story, as the story, and the date, of the foundation of Bam. If so, this date goes back to the late, or mid, Parathion period although a thorough scientific and archeological inspection of the site is still needed. There are some signs and indications like some Parathion coins found here - which make it a safe guess to assume that the nucleus part of the town and the citadel belonged to the Parthian period in its original form.

Judging from the story of Haftvad` and also by comparing the ruins of Ghal-e-Do (the Maiden Fortress) to the north of Arg, and the original structure of the citadel, with the Parthian town model (like the ruins of Parthaunisa in Turkmenistan), it is obvious that originally the town and the residential quarters for the common people were located couple of miles to the west of the Arg, in the place of today`s Koozeran-corresponding the Kojaran of the Shahnameh and the adjacent Dehshotor quarters, while the residence of the governing prince was in the Ghal-e-Dokhtar, where, according to the Parthian- and maybe Achamenide-model, it was also the temple for the official court religion.

There is an ornamental figure carved on the wall of an altar on the eastern side of Ghal-e-Dokhtarl which resembles very much to a similar figure on the altar of another very important, hut, alas, a very little known site about 2 Km to the east of the Arg, known as (Char Taghi`. As the story goes, after Haftvad rebelled against the governing prince and killed him, he made a citadel and a fortress on a rock-hill to the west of the town, corresponding to the present site of the Arg. After Haftvad was defeated and killed by Ardashir, the victorious king destroyed the main citadel in the fortress and built a fire-temple in it instead, which, it is believed, was turned into the existing main observation tower and the Char-Fasl building in the Islamic period. In any event, 2000 years of history, with all its ups and downs, with all its wars, internal strives, periods of peace, of calm, of blooming, of blood, of destructions, of developments, of massacres,.., have left their imprints on this site of history which cries out the transient nature of (being) and the external essence of the universe.