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 Mundo. 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.