(Ὑπατία), a lady of Alexandria, daughter of Theon, by whom she was instructed in philosophy and mathematics. She soon made such immense progress in these branches of knowledge, that she is said to have presided over the Neoplatonician school of Plotinus at Alexandria, where she expounded the principles of his system to a numerous auditory. She appears to have been most graceful, modest, and beautiful, but nevertheless to have been a victim to slander and falsehood. She was accused of too much familiarity with Orestes, prefect of Alexandria, and the charge spread among the clergy, who took up the notion that she interrupted the friendship of Orestes with their archbishop, Cyril. In consequence of this, a number of them, at whose head was a reader named Peter, seized her in the street, and dragged her from her chariot into one of the churches, where they stripped her and tore her to pieces. Theodoret accuses Cyril of sanctioning this proceeding; but Cave (Script. Eccl. Hist. Lit. vol. i.) holds this to be incredible, though on no grounds except his own opinion of Cyril's general character. Philostorgius, the Arian historian, urges her death as a charge against the Ilomoousians. Synesius valued her greatly, and addressed to her several letters, inscribed τῇ φιλοσόφῳ, in one of which he calls her mother, sister, mistress, and benefactress. Suidas says that she married Isidorus, and wrote some works on astronomy and other subjects. In Stephanus Baluzius (Concil. i. p. 216) an epistle is extant professing to be Hypatia's addressed to Cyril, in which she advocates the cause of Nestorius, and regrets his banishment; but this must be spurious, if it be true, as Socrates asserts that she was killed A. D. 415, for Nestorius was not banished till A. D. 436. (Socrat. 7.15; Niceph. 14.16; Menage, Hist. Mulierum Philosoph. 49; Suidas, s.v. J. Ch. Wernsdorf, Dissertat. Acad. IV. de Hypartia, Viteberg. 1747.)