Ptolemy’s map extends 180 degrees West-East and 90 degrees South-North: one quarter of the earth’s surface. The prime meridian (now Greenwich) runs through the Fortunate Islands (the Canaries) which was the most westerly point of the known world. Although published in the late 15th century, this map presents the world-view of the late Roman period; its contemporary importance lies in its mathematical construction. The geographical oddity which is the hallmark of the Ptolemaic map is the land-mass linking Africa to south-east Asia, rendering the Indian Ocean a vast landlocked sea. Ptolemy considered this a theoretical necessity to balance the northern continents. The twelve faces represent the classical winds. Editions of Ptolemy’s work were published in Italy from 1477 onwards and are among the earliest printed maps. This edition of 1482 printed in Ulm contains a notorious mistake: both Tropics have been named ‘Tropicus Cancri'.