, of Alexandria, a celebrated Greek philosopher and mathematician, flourished in the fourth century, about the year 380, in the time of Theodosius the Great; but the time and manner of his death are unknown. His genius and disposition for the study of philosophy were very early improved by a close application to study; so that he acquired such a proficiency in the sciences as to render his name venerable in history; and to procure him the honour of being president of the famous Alexandrian school. One of his pupils was the celebrated Hypatia, his daughter, who succeeded him in the presidency of the school; a trust, which, like, himself, she discharged with the greatest honour and usefulness. (See Hypatia.)

The study of nature led Theon to many just conceptions concerning God, and to many useful reflections in the science of moral philosophy; hence, it is said, he wrote with great accuracy on divine providence. And he seems to have made it his standing rule, to judge the truth of certain principles, or sentiments, from their natural or necessary tendency. Thus, he says, that a full persuasion, that the Deity sees every thing we do, is the strongest incentive to virtue; for he insists, that the most profligate have power to refrain their hands, and hold their tongues, when they think they are observed, or overheard, by some | person whom they fear or respect. “With how much more reason then,” says he, “should the apprehension and belief that God sees all things, restrain men from sin, and constantly excite them to their duty?” He also represents this belief concerning the Deity as productive of the greatest pleasure imaginable, especially to the virtuous, who might depend with greater confidence on the favour and protection of Providence. For this reason, he recommends nothing so much as meditation on the presence of God; and he recommended it to the civil magistrate, as a restraint on such as were profane and wicked, to have the following inscription written in large characters at the corner of every street: “God sees thee, O sinner.

Theon wrote notes and commentaries on some of the ancient mathematicians. He composed also a book entitled “Progymnasmata,” a rhetorical work, written with great judgment and elegance; in which he criticised on the writings of some illustrious orators and historians; pointing out, with great propriety and judgment, their beauties and imperfections; and laying down proper rules for propriety of style. He recommends conciseness of expression, and perspicuity, as the principal ornaments. This work was printed at Basle in 1541, but the best edition is that of Leyden, 1626, 8vo. 1