COSMAS INDICOPLEUSTES. – Byzantine writer of the first half of the 6th century. Born in Egypt, he was first a merchant and around 520 he traveled to eastern Africa, Arabia, and as far as India: hence his epithet *Indicopleustes*, i.e., “navigator of the Indies.” Later he became an anchorite and lived in Alexandria and perhaps also on Mount Sinai. Gifted with powers of observation and broad learning, he worked for about twenty years, from 535 onward, on his work *Χριστιανική τοπογραφία* (*Christian Topography*), in 12 books and accompanied by geographical-cosmological drawings, which were particularly appreciated.
Written in a heavy style, the work today stands as a disordered repertory of the most disparate information, especially for the history of geography and cosmology, but also for Greek Christian literature, liturgy, archaeology, etc. As already appears from the title, the principal aim of C. I. was to demonstrate that a Christian must follow the astronomical-cosmological concepts found in the Bible (i.e., those of ancient Judaism), absolutely rejecting Greek concepts (i.e., essentially those of Ptolemy) as false and heretical. Indeed, C. I. depicts the universe as an immense chest whose lid is the upper heaven; beneath it there is a plane that divides the universe lengthwise and is the firmament or lower heaven; the space between the two heavens is the abode of God and the elect, while the earth, which is beneath the firmament, is the abode of man.