MATHEMATICIAN, ASTRONOMER, GEOGRAPHER, ARCHITECT

Life
Theodosius, a native of Tripolis in Bithynia, is cited by Strabo and Suidas. He rekindled an interest in astronomy and geography, and is considered a forerunner of the great Greek astronomer Ptolemy.


Work
His principal works are:

"On days and nights": 2 books. Survives in Latin translation. Treatise on astronomy, with 32 propositions on the length of the night and the day according to the season and the geographical latitude. Also treats of problems relating to the calculation of time. Vitruvius records that Theodosius invented a device to calculate geographical latitude.

"On habitations": Treatise on geography, with elements of mathematical geography relating to the earth's climatic zones, which he called "habitations". This is the first work of mathematical geography.

"Spherics": 3 books. Treats of spherical sections. 25 manuscripts survive, in Latin translation.

"Memorandum on Archimedes' "Mechanics"": Lost. Commentary on Archimedes' "Mechanics".

"Astrology": Lost. Treated problems in astronomy as well as astrology.

"Drawing houses": Treatise on problems of architecture. Fragments survive.