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
Lighthouse of Alexandria this mole, and the Ras el-Tin promontory represents all that is left of the island of Pharos, the site of the lighthouse at its eastern point having been weathered away by the sea. The lighthouse was constructed in the 3rd century BC. After Alexander the Great died, the first Ptolemy (Ptolemy I Soter) announced himself king in 305 BC, and commissioned its construction shortly thereafter. The building was finished during the reign of his son, the second Ptolemy (Ptolemy II Philadelphus). It took twelve years to complete, at a total cost of 800 talents, and served as a prototype for