Very popular in medieval Russia (as, indeed, and in the Christian East in general) "Christian topography" of Cosmas (Kosma) Indicopleustes (literally - "plavatel to India"), the Byzantine merchant and later a monk who lived in the VI century. "Christian Topography" (in the Slavonic translation of "The Book about Christ, enveloping the whole world") is essentially a theological treatise cosmographical - medieval encyclopedia of the inhabited world...