This study represents the historical geographer’s approach to the History of cartography. Modern historians of the Roman Empire and archaeologists misuse geographical information from Ptolemy’s map of the Caucasus–Ptolemy’s 3rd Map of Asia in the standard set of twenty-seven maps, including a world map, all in the Ptolemaic model, with twenty-six regional maps. In fact, modern writers on ancient history think that the story of maps is linear–beginning, middle and end. But the case of Ptolemy is typical in that his work began to have a powerful influence in the fifteenth century. After Ptolemy’s death in the second half of the second century, however, his Geography had disappeared for a thousand years, and with it the idea of coordinate-based mapping according to a mathematical grid system. No original copies from Ptolemy’s own time have survived. A medieval Greek copy without maps only reappeared in fourteenth-century Florence, with maps first drawn by Florentine cosmographers in further copies in 1415. Here we have an antinomia, an apparent contradiction, which nothing but the History of cartography solves as “Ptolemy’s paradox”. Ptolemy’s maps of Roman Britain makes a striking contrast with the map showing our present state of knowledge about the British Isles. It has long been recognized as a puzzling fact that, in Ptolemy’s map of the British Isles, the shape of Britain is turned abruptly to the east from the latitude 55° north, corresponding to Scotland, so as to make a right angle with the southern part of the country–England and Wales. But what is unknown still is how Colchis (West Georgia), Ibería of the Caucasus (East Georgia), Albània of the Caucasus (Alania / Daghestan), Upper or Greater Armenia, Media (Osroenê / upper Mesopotamia) and Assyria are misaligned west-east, and distorted as well. The “dogleg” appearance of the Mescit Mountains (currently Turkey) is a distorted feature which occurs exclusively on Ptolemy’s map of the Caucasus. Since A.D. 114 the three Kingdoms of Colchis, Ibería and Albània of the Caucasus had been federated with Rome. Since A.D. 117 the neighbouring provinces of Greater Armenia, Media and Assyria had been annexed to the Roman Empire, when Ptolemy composed his system of geography about A.D. 150. As a result, the Ptolemaic map of the Caucasus is quite useless in the history of the Caucasus. Ignoring the set of Ptolemy’s maps of all the countries and even the question of Ptolemy’s distortion, however, modern historians of ancient Rome and archaeologists in the Caucasus consult Ptolemy’s 3rd Map of Asia as a source of primary information.