author of the only ancient treatise on geography in classical Latin, De situ orbis (“A Description of the World”), also known as De chorographia (“Concerning Chorography”). Written about AD 43 or 44, it remained influential until the beginning of the age of exploration, 13 centuries later. Though probably intended for the general reader, Mela's geography was cited by Pliny the Elder in his encyclopaedia of natural science as an important authority.

Though the work was largely a borrowing from Greek sources and contained information that was frequently obsolete, it was unique among the ancient geographies in that it divided the Earth, which Mela placed at the centre of the universe, into five zones: a northern frigid zone, a northern temperate zone, a torrid zone, a southern temperate zone, and a southern frigid zone. The two temperate zones were habitable, but only one, the northern, was known. The southern was unattainable by people of the north because of the necessity of passing through the unbearable heat of the intervening torrid zone in order to reach it. According to Mela, the ocean surrounding the Earth cut into it in four seas, the most important being the Mediterranean. He avoided technical details, such as distances, but usually included short phrases describing the places mentioned. Less was said of familiar regions than of distant countries, where even fabulous material was included.