Heliopolis (ancient Egypt) from him the true length of the year and month, upon which he formed his octaeterid, or period of 8 years or 99 months. Ptolemy II had Manetho, the chief priest of Heliopolis, collect his history of the ancient kings of Egypt from its archives. The later Ptolemies probably took little interest in their "father" Ra, and Alexandria had eclipsed the learning of Heliopolis; thus with the withdrawal of royal favour Heliopolis quickly dwindled, and the students of native lore deserted it for other temples supported by a wealthy population of pious citizens. By the 1st century BC, in fact,
Chronology of the ancient Near East tablets or inscriptions in question still have value, though one does have to keep the slant in mind. Keeping historical lists of rulers was traditional in the ancient Near East. Covers rulers of Mesopotamia from a time "before the flood" up to the fall of the Isin Dynasty. For many early city-states it is the only source of chronological data. A major problem is that many early rulers are listed with fantastically long reigns. There has been some speculation that this stems from an error transcribing from the base 60 arithmetic of the Sumerians to the decimal-based system of the