The Ptolemaic Legacy

The Mouseion / Library

When Ptolemy Soter assumed power, he asked Demitrius Phalerus, a follower of Aristotle, to found a library system at Alexandria that would rival that of Athens. The Alexandrian Mouseion, however, far superseded its Greek prototype to become an intellectual and scientific institution; a university system rather than a bibliotheca. It was here, in the third century BC, that Archimedes invented the pump still in use today and known as Archimedes' screw, and, in the second century BC, that Hypsicles first divided the circle of the zodiac into 360 degrees. Ancient historians claim that the library's 500,000 book collection was so comprehensive that no manuscript was available in any library worldwide that was not available in Alexandria.

Mathematics

Have you ever heard of Euclidean Geometry? Did you know that Euclid lived, developed his theories, and wrote Elements at the Alexandria Mouseion during the reign of Ptolemy II Philadelphus? In his Elements, Euclid provided a comprehensive analysis of geometry, proportions, and theory of numbers. His other notable contribution, Optics, is a treatise of geometrical optics.

In the Mouseion, the first studies of conic sections (Ellipse, Parabola, and Hyperbola) were carried out by Conon of Samos and Appolonius of Perga. Later, Pappus wrote his Collection, Menelaus studied spherical triangles, and Sporus, Heron, Diophantus, Theon, and his daughter Hypatia, taught mathematics.

Geography and Astronomy

Have you ever heard of the Alexandrian astronomer Eratosthenes? Do you know that he measured the Earth diameter more than 15 centuries before Copernicus and Galileo were even born? Eratosthenes was born in Cyrene in 276 BC, and, upon the death of Callimachus, was offered the post of "Chief Librarian of the Mouseion", a most highly respected position. His measurement of the Earth diameter was the most exciting of his achievements, although not the only one. He believed the Earth is round, and knew that shadows cast by the sun in Alexandria and Aswan (Syene) were unequal. He took measurements inside a deep well in Syene and along an obelisk in Alexandria a year apart, on the same day of the year. Knowing the distance between both cities, and using simple calculations, he estimated the Earth diameter at 7,850 miles. Today, we know that Eratosthenes' estimate was only about 0.5% off.

The great Alexandrian geographer and astronomer Claudius Ptolemy was born in AD 100. The work he developed was a product of the knowledge compiled in the Mouseion during the Ptolemaic period. He wrote many books including Geography, Almagest, Handy Tables, and Planisphaerium. He proposed the "Ptolemaic" Theory which states that Universe revolves around the Earth. The theory was adopted by scientists until the sixteenth century.

Aristarchus of Samos, Eratosthenes' co-worker in Alexandria, had suggested in the third century BC the heliocentric hypothesis, which states that the Earth and the planets revolve around the Sun. Ironically, fifteen centuries later, people were still arguing whether or not the earth is flat. Unfortunately, very little is known of Aristarchus' work and writings which perished along with the Library.

The Monuments

The Lighthouse

The construction of the Lighthouse of Alexandria was completed during the reign of Ptolemy II Philadelphus. It ranked as one of the Seven Wonders of the Ancient World. In fact, it was the only Wonder that had a practical secular use. This blend of beauty and scientific practicality was exclusive to the Ptolemies and their culture. Its architect, Sostratus, was a contemporary of Euclid. The full design of the Pharos and its accessories was carried out at the Mouseion. It stood approximately 150 meters high (a 50-storey modern building). Most impressive, was the mysterious "mirror" that was installed at the building summit. It was capable of detecting ships in the sea that were invisible to the naked eye and was used to magnify the intensity of the light emitting from the "lantern" at the top. A statue of Poseidon decorated the summit of the building.

The Palace

The Ptolemaic Palace system covered the promontory of Silsila, and stretched south and west. Recent archeological evidence suggests that the buildings reached as far west as today's Raml Station,that is, about a mile along the shores of the Eastern Harbour. The palace system was connected to the Mouseion, and the Caesarium which was built later by Cleopatra in honor of Julius Caesar. An Island Palace, called Antirrhodus, was erected off of Alexandria's mainland in the Eastern Harbour. In later periods, water levels rose, and the Island subsided; remains of the Island Palace are submerged underneath the water of the Harbour.

The Temple of Serapis

Built in honor of the Egyptian God, Osiris, the temple was home to worshippers of all sects. Osiris, Zeus, Pluto, Apis, and others all lived in harmony there. It was the last stronghold of Paganism against Christianity. Built along the lines of Greek architecture, the temple is located in Kom-El-Dikka, site of the ancient town of Rhakotis.

The Heptastadion Dyke

Connecting the Island of Pharos with Egypt's mainland was part of Alexander's plan. A dyke, the Heptastadion (seven stades long) was completed during the Ptolemaic period, and provided not only easy access to Pharos, but a double harbor to the city. Later on, the area around the Heptastadion silted and formed the isthmus known today as Mansheya.

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