“Pomponius Mela is a puzzle, and so is his one known work, The Chorography,” writes Frank E. Romer in Pomponius Mela’s Description of the World. In that series of three books, which seems not to have contained any maps itself, Mela divides the Earth into two rough “hemispheres” and five zones, two of them cold, one of them hot, and two in between.

http://www.openculture.com/2018/04/a-map-shows-how-the-ancient-romans-envisioned-the-world-in-40-ad.html

Good enough to build a setting around. At least as true in the game as it was in the “real” world.