History of Alexandria Severus after temporary abolition by Augustus. Monumental buildings were erected in Alexandria through the third century BC. The Heptastadion connected Pharos with the city and the Lighthouse of Alexandria followed soon after, as did the Serapeum, all under Ptolemy I. The Museion was built under Ptolemy II; the Serapeum expanded by Ptolemy III Euergetes; and mausolea for Alexander and the Ptolemies built under Ptolemy IV. The Ptolemies fostered the development of the Library of Alexandria and associated Musaeum into a renowned center for Hellenistic learning. Luminaries associated with the Musaeum included the geometry and number-theorist Euclid; the astronomer Hipparchus; and
Ptolemaic cult of Alexander the Great propaganda to support the claims of his own dynasty. As part of this effort, Alexander was elevated from a simple patron god of Alexandria to the status of a state god for the Greek populations of the entire Ptolemaic empire, even beyond the confines of Egypt. During the early Ptolemaic dynasty (), Ptolemy I began the construction of the Tomb of Alexander the Great in Alexandria (the , "sēma", ), and appointed a priest (, "hiereus") to conduct religious rites there. This office quickly advanced to become the highest priesthood in the Ptolemaic Kingdom, its prominence underscored by its eponymous