Apollonius of Perga

Apollonius of Perga (Greek: Ἀπολλώνιος ο Περγαῖος; Latin: Apollonius Pergaeus; late 3rd - early 2nd centuries BC) was a Greek geometer and astronomer known for his theories on the topic of Conic sections. Beginning from the theories of Euclid and Archimedes on the topic, he brought them to the state they were in just before the invention of analytic geometry. His definitions of the terms ellipse, parabola, and hyperbola are the ones in use today.

Apollonius worked on many other topics, including astronomy. Most of the work has not survived except in fragmentary references in other authors. His hypothesis of eccentric orbits to explain the apparently aberrant motion of the planets, commonly believed until the Middle Ages, was superseded during the Renaissance.

For such an important contributor to the field of mathematics, scant biographical information remains. The 6th century Palestinian commentator, , on Apollonius’ major work, Conics, states:

“Apollonius, the geometrician, ... came from Perga in Pamphylia in the times of Ptolemy Euergetes, so records Herakleios the biographer of Archimedes ....”

Perga at the time was a Hellenized city of Pamphylia in Anatolia. The ruins of the city yet stand. It was a center of Hellenistic culture. Euergetes, “benefactor,” identifies Ptolemy III Euergetes, third Greek dynast of Egypt in the diadochi succession. Presumably, his “times” are his regnum, 246-222/221 BC. Times are always recorded by ruler or officiating magistrate, so that if Apollonius was born earlier than 246, it would have been the “times” of Euergetes’ father. The identity of Herakleios is uncertain. The approximate times of Apollonius are thus certain, but no exact dates can be given. Specific birth and death years stated by the various scholars are only speculative.

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