Adjoining these great halls devoted especially to the worship of the god, were hundreds of courts, passages, colonnades and rooms, and others not less numerous lay underground. There were long rows of rooms containing above a hundred thousand rolls of books, the famous library of the Serapeum, with separate apartments for readers and copyists; there were store-rooms, refectories and assembly-rooms for the high-priests of the temple, for teachers and disciples; while acrid odors came up from the laboratories, and the fragrance of cooking from the kitchen and bake-houses. In the very thickness of the walls of the basement were cells for penitents and recluses, long since abandoned, and rooms for the menials and slaves, of whom hundreds were employed in the precincts; under ground spread the mystical array of halls, grottoes, galleries and catacombs dedicated to the practice of the Mysteries and the initiation of neophytes; on the roof stood various observatories—among them one erected for the study of the heavens by Eratosthenes, where Claudius Ptolemaeus had watched and worked. Up here astronomers, star-gazers, horoscopists and Magians spent their nights, while, far below them, in the temple-courts that were surrounded by store-houses and stables, the blood of sacrificed beasts was shed and the entrails of the victims were examined.
The house of Serapis was a whole world in little, and centuries had enriched it with wealth, beauty, and the noblest treasures of art and learning. Magic and witchcraft hedged it in with a maze of mystical and symbolical secrets, and philosophy had woven a tissue of speculation round the person of the god. The sanctuary was indeed the centre of Hellenic culture in the city of Alexander; what marvel then, that the heathen should believe that with the overthrow of Serapis and his temple, the earth, nay the universe itself must sink into the abyss?