This vision of the world dates back to the Greece of the sixth century BC. According to the theorist Parmenides the world was divided into five zones, two of them freezing, two temperate and one that was very hot around the Equator. A great ocean ran through the middle of the equatorial zone and this linked up with another that flowed from north to south. Only the northern temperate zone was known to be inhabited. This map dates from the ninth century and illustrates the text of the Commentary on the Dream of Scipio by the Roman writer, Macrobius (395-436) . It shows some detail for the top of the equatorial zone and for the northern temperate zone. Reading from right to left beneath the northern, freezing zone, which is uninhabitable ('inhabitabilis') is the Caspian Sea, beneath it the Indian Ocean, next to the left is a shape indicating the Black Sea and next to it Greece (unnamed) and then Italy ('italia') and a bump representing Spain. Beneath all of these is a horizontal strip representing the Mediterranean and beneath it an L shaped Red Sea. Forming a rough triangle at the left, with a big circle in the middle, are the fabled Orkney Islands ('Orcades'). The rest of the British Isles is missing.