Theon of Alexandria

Theon (Greek: Θέων, ca. 335 - ca. 405 AD) was a Greek^[1] (or as some scholars contend an Egyptian)^[2] scholar and mathematician who lived in Alexandria, Egypt. The biographical tradition (Suda) defines Theon as "the man from the Mouseion"; actually, both the Library of Alexandria and the Mouseion may have been destroyed a century before by the Emperor Aurelian during his struggle against Zenobia. Some scholars think that they were closed by the patriarch Theophilus on order of the Christian Roman emperor Theodosius I in 391 AD.
Theon was the father of the mathematician and pagan martyr Hypatia of Alexandria whose murder is attributed by Socrates Scholasticus to "political jealousy" which instigated mob violence.

Theon's most durable achievement may be his edition of Euclid's Elements, published around 364 and authoritative into the 19th century. The bulk of Theon's work, however, consisted of commentaries on important works by his Hellenistic predecessors. These included a "conferences" (Synousiai) on Euclid, and commentaries (Exegeseis) on the Handy Tables and Almagest of Ptolemy, and on the technical poet Aratus.

In one of the commentaries on the Handy Tables, he is the first author to describe the theory of trepidation of the equinoxes, as an alternative to precession. Theon described but did not endorse this theory.

Notes

^ Tihon, Anne, "Theon of Alexandria and Ptolemy's Handy Tables", In Ancient Astronomy and Celestial Divination. Dibner Institute studies in the history of science and technology. Edited by N.M. Swerdlow. Cambridge, MA: MIT Press, 1999, p. 357.
G. J. Toomer, "Theon of Alexandria," in Dictionary of Scientific Biography 13: 321-325.
T L Heath, A History of Greek Mathematics (2 Vols.) (Oxford, 1921).^{page # needed}
O Neugebauer, A history of ancient mathematical astronomy (New York, 1975).^{page # needed}
A Rome, Commentaires de Pappus et de Théon d'Alexandrie sur l'Almageste Tome III. Théon d'Alexandrie (Rome, 1943).^{page # needed}
A Tihon (ed.), Le 'Grand commentaire' de Théon d'Alexandrie aux 'Tables faciles' de Ptolémée Livre I (Vatican City, 1985).^{page # needed}
A Tihon (ed.), Le 'Grand commentaire' de Théon d'Alexandrie aux 'Tables faciles' de Ptolémée Livre II, III (Vatican City, 1991).^{page # needed}
^ George Sarton (1936). "The Unity and Diversity of the Mediterranean World", Osiris 2, p. 406-463 [429, 463].