a distinguished saint and martyr of the early Christian church, was a native of Arabia, where, along with his brother Damianus, he practised medicine gratuitously. The two brothers adopted this profession from the idea that by means of it they might most efficiently benefit their fellow-creatures. After a short but eminently useful career, they both perished in the persecution organized by Diocletian against the Christians, A.D. 303-311.

Cosmas, bishop of Maiuma in Palestine during the first half of the eighth century, was originally a monk of Jerusalem, and gained a great reputation by the sacred hymns which he composed for the service of the Greek church. These hymns—some of which are acrostics—are still for the most part in MS., though a few of them were at one time issued from the Aldine press.

Cosmas, surnamed Indicopleustes from the fact of his having sailed over the eastern seas, was a native of Egypt, and lived during the first half of the sixth century of the Christian era. In early life he travelled as a merchant through the East as far as India, visiting Arabia and Persia, and navigating the adjoining seas. In the course of his wanderings he amassed much information concerning the topography, history, and antiquities of the countries which he visited, and the mode of life, manners, and customs of the inhabitants. The result of his researches he embodied in his Topographia Christiana, sive Christianorum opinio de Mondo. Besides this work, Cosmas compiled a series of astronomical tables, a universal cosmography, an exposition of the Psalms, and a commentary on Canticles,—which treatises have perished.