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,
Library of Alexandria cultural imperialism". These rulers therefore had a vested interest to collect and compile information from both the Greeks and from the far more ancient kingdoms of the Near East. Libraries enhanced a city's prestige, attracted scholars, and provided practical assistance in matters of ruling and governing the kingdom. Eventually, for these reasons, every major Hellenistic urban center would have a royal library. The Library of Alexandria, however, was unprecedented due to the scope and scale of the Ptolemies' ambitions; unlike their predecessors and contemporaries, the Ptolemies wanted to produce a repository of all knowledge. The Library was one of the