Theodosius of Bithynia

Theodosius of Bithynia (Greek: Θεοδόσιος; 2nd–1st century BC) was a Hellenistic astronomer and mathematician from Bithynia who wrote the Spherics, a treatise about spherical geometry, as well as several other books on mathematics and astronomy, of which two survive, On Habitations and On Days and Nights.

Life

Little is known about Theodosius' life. The Suda (10th-century Byzantine encyclopedia) mentions him writing a commentary on Archimedes' Method (late 3rd century BC),[1] and Strabo's Geographica mentioned mathematicians Hipparchus (c. 190 – c. 120 BC) and "Theodosius and his sons" as among the residents of Bithynia distinguished for their learning.[2] Later Vitruvius (1st century BC) mentioned a sundial invented by Theodosius. Thus Theodosius lived sometime after Archimedes and before Vitruvius, likely contemporaneously with or after Hipparchus, probably sometime between 200–50 BC.[3]

Historically he was called Theodosius of Tripolis due to a confusing paragraph in the Suda which probably fused the entries about separate people named Theodosius,[4][1] and was interpreted to mean that he came either from the Tripolis in Phoenicia or the one in Africa.[5] Some sources claim he moved from Bithynia to Tripolis,[6] or came from a hypothetical city called Tripolis in Bithynia.[7]

Works
See also: Theodosius' Spherics

Theodosius' chief work, the Spherics (Greek: τὰ σφαιρικά tá sphairiká), provided the mathematics for spherical astronomy. Euclid's Phenomena and Autolycus's On the Moving Sphere, both dating from two centuries prior, make use of theorems proven in Spherics, so it has been speculated that they may have expected readers to be familiar with a treatise on elementary spherical geometry, perhaps by Eudoxus of Cnidus (4th century BC), on which the Spherics may have been based.[8] However, no mention of this hypothetical earlier work or its author remains today.

The Spherics is reasonably complete, and remained the main reference on the subject at least until the time of Pappus of Alexandria (4th century AD).[9] The work was translated into Arabic in the 10th century, and then into Latin in the early 16th century, but these versions were faulty. Francesco Maurolico translated the works later in the 16th century.[9]

In addition to the Spherics, two other works by Theodosius have survived: On Habitations, describing the appearances of the heavens at different climes and different times of the year, and On Days and Nights, a study of the apparent motion of the Sun. Both were published in Latin in the 16th century.[10] Theodosius was cited by Vitruvius as having invented a sundial suitable for any place on Earth.[9]

Notes
  1. Adler, Ada, ed. (1931). "Theodosius". Suidae Lexicon (in Greek). Vol. 2. p. 693 (Translation from Dictionary of Scientific Biography): Theodosius, philosopher, wrote Sphaerics in three books, a commentary on the chapter of Theudas, two books On Days and Nights, a commentary on the Method of Archimedes, Descriptions of Houses in three books, Skeptical Chapters, astrological works, On Habitations. Theodosius wrote verses on the spring and other types of works. He was from Tripolis.
    This text was historically taken to refer to a single person, but the sentences about the Theodosius from Tripoli who wrote verses about the spring were likely intended to represent a separate entry. Furthermore, Theudas lived after Theodosius of Bithynia; the commentary on Theudas and Skeptical Chapters were written by someone else, perhaps a different Theodosius. The other listed works were by the Theodosius who wrote the Spherics, including presumably the (now-lost) commentary on Archimedes' Method.
  2. Strabo (1852). Meineke, August (ed.). Strabonis Geographica (in Greek). Vol. 2. Leibzig: Teubner. IB ¶4.9, C.566, p. 795 lines 13–14.
  3. Sidoli & Thomas 2023, "Theodosios's time and works", pp. 3–5.
  4. Neugebauer 1975, p. 750.
  5. Stone, Edmund (1721). Clavius's Commentary on the Sphericks of Theodosius Tripolitae: or, Spherical Elements. London: J. Senex. Preface. Translated from Clavius, Christopher (1586). Theodosii Tripolitae Sphaericorum Libri III (in Latin). Rome: Ex Typographia Dominici Basae.
  6. Rozenfeld, Boris Abramovich (1988). A History of Non-Euclidean Geometry. Translated by Shenitzer, Abe. Springer. p. 3. Translated from Istoriya Neevklidovoi Geometrii (in Russian). Moscow: Nauka. 1976.
  7. Tripolis, Greek for "three cities", was the name of several ancient cities. See Tripolis (disambiguation).
  8. Ivor Bulmer-Thomas, "Theodosius of Bithynia," in Dictionary of Scientific Biography, Encyclopedia.com, 2008.
  9. Heath 1911, p. 771.
  10. Heath 1911, pp. 771–772.

References
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.