It's impossible to describe the impact this artifact has when seeing it in person and up close. It was not enclosed in glass and so you were able to get your nose very close in to look at the heiroglyphic inscriptions -- but not touching.
Information from the Franck Goddio Society Website:
The fragments covered with Egyptian figures and hieroglyphic texts which Franck Goddio has discovered in the waters of Aboukir Bay are part of a monument which is truly one of its kind: the "Naos of the Decades". They allow us to understand better, and to date into the 5th century B.C., a set of texts which are the most ancient known documents bearing witness to the origins of classical astrology, born in Egypt from a combination of assyrian astrology and the pharaonic concept of the calendar.
The pharaonic fragments collected by Franck Goddio in 1998 contribute another twist to the ups and downs of a monument of exceptional importance; they also add a decisive chapter to an avenue of research which alters the history of astrological beliefs: the "Naos of the Decades".
In the 4th century B.C., in the township of Saft on the eastern border of the Nile Delta, Pharaoh Nectanebo I dedicated a monolithic basalt chapel of the kind called naos by egyptologists. Its surfaces were engraved with images and inscriptions representing and explaining the 36 decades, which are the ten-day periods defined by the appearance and disappearance of significant stars called the decans.
Observation of the movement of these decans was used to count the night hours. Then, in the 9th century B. C., the Egyptians attributed these celestial figures with the menacing power of influencing human destiny. When the Greeks later brought to Alexandria an astrology with roots reaching far back in time to the Assyrians and Chaldaeans, the Egyptian decans were introduced as subdivisions of the twelve signs of the zodiac (which they remained even up to today’s practitioners of astrology). Already at the time of the Ptolemies, a number of Alexandrian intellectuals, philosophers and astronomers strove to penetrate the immemorial beliefs which the Egyptian priests were supposed to have gleaned from the god Thot - Hermes Trismegistos for the Greeks. These beliefs then grew further under the Roman domination, elaborating the future occultist and hermetist knowledge which pervaded all through the Middle Ages. During Roman times (between the 1st and 3rd century A.D.), the Naos of the Decades was transferred from Saft to a temple in Canopus, the sacred place of the cult of Serapis and Isis. The subsequent Christianisation of this Canopian hotbed of obstinate resistant to pagan beliefs was difficult and uphill work, ending in the dramatic, violent events which are known. The Christians violently smashed and destroyed the stone chapel which was considered an outstanding example characteristic of pagan idolatry and disturbing demonic "superstitions"… Its fragments were dispersed over a wide area when a major part of the city was submerged (current research in the bay also hopes to determine more precisely the date of this event).
In 1940, divers under the direction of Prince Omar Tousson, a pioneer of underwater research in Aboukir Bay, reported the presence of two great slabs of stone representing the rear and the floor of the tabernacle, which were subsequently put into the Greco-roman Museum in Alexandria.
In 1952, it was discovered that a pyramid block which had been kept in the Louvre ever since the French restoration after 1815, was in fact the top of the same naos; and in 1954, it could be established that this fragment had originally been discovered on land by the naturalist Sonnini de Manoncour in 1777, who had dug it out of the sands of the beach outside Aboukir village.
Now, out of the sea, Franck Goddio has brought to light several pieces which will, in fact, enable the reconstruction almost entirely of the two lateral surfaces.
The study of the available texts had allowed several scientists to undertake a theoretical reconstitution of the complex iconographic system which sorted and arranged the 36 decades, while the hieroglyphic captions permitted the interpretation of the mysterious figures representing the course of the 36 decans through the night. The notes defining the influence which each decade operated on nature, animals, human communities and individual health, were discovered to be of the same literary style and genre as found in Greek and Latin treatises of the Roman period, but were written in Egyptian hieroglyphs of the 4th century B. C. The stars were then thought to strike the order of Pharaoh’s kingdom and of the various bordering states, which are concepts manifestly absorbed during the contacts between Egypt and Assyria at the turn of the 8th to the 7th century B.C.
Museography: the additions collected by Franck Goddio allow first of all to envisage an almost integral restoration of a monument exceptional by its quality and dimensions.
Cultural History:In addition, they contribute decisive elements for historians of ancient cultures. The particular way in which the doctrine concerning the deities of the decades has been inserted into the specific geographical and religious reality of Saft as well as into the Egyptian myth of Genesis, is now accessible through a text of a kind which was so far to tally unknown, preserved on one of the numerous fragments. Furthermore, mention of the Medes on another of them determines that the entire document could not have been created before the 5th century B.C., when Egypt became part of the Persian Empire. The "Naos of the Decades" also tells us that a scholar from the Egyptian province - long before the hellenistic period and outside any reference to the zodiacal cycle - had attributed the same kind of political influence to the celestial deity which had created the decans and controlled the decades, as Assyrian astrologers had attributed to the moon and the planets, a genre unknown to Egyptian hemerologies and menologies.
It would indeed be wonderful if further diving could reveal the few pieces still missing. Nevertheless, it will certainly require much time and effort to collate all the inscriptions on the available stones - some of which are heavily corroded - and then undertake the philological research into the precise sense of certain words in the texts, as well as a renewed reflection on the Egyptian concepts concerning the decans.
For some fascinating background information about the decans, see Kidneys in Ancient Egypt, by Rosalind Park.