Ptolemaic World Map from ‘Geographia’
When the works of the classical geographer, astronomer and mathematician Claudius Ptolemy began to emerge from obscurity in the early 1400s, his most famous book 'Geographia' (sometimes called 'Cosmographia') was translated from Greek into Latin.Full description »
When the works of the classical geographer, astronomer and mathematician Claudius Ptolemy began to emerge from obscurity in the early 1400s, his most famous book 'Geographia' (sometimes called 'Cosmographia') was translated from Greek into Latin. So began a craze for constructing maps according to Ptolemy’s scientific methods, using the ancients’ system of locating places by their co-ordinates of latitude and longitude. Even after the great geographical discoveries of the Renaissance, cartographers were still constructing maps on Ptolemy’s principles up to about 1570, or at least using them as a basis for authority.
Printed in 1490 from the same plates as the 1478 Rome edition of 'Geographia', this map shows the world as it was known to a citizen of Roman Alexandria: it extends from the Fortunate Islands (the Canaries) in the west to the middle of China (named 'Serica' for 'silk' on the map) in the east, and from Thule in the north to the Horn of Africa in the south. It is constructed according to Ptolemy’s conical (‘lazy man’s’) projection, and has degrees of longitude marked along the upper and lower edges, with latitude along the right. Arranged on the left side border are ‘clima’, by which latitude is measured in hours of daylight of the longest day, from twelve hours at the equator to twenty hours in the north.
Following Ptolemy’s teachings, the map is plainly drawn and clearly legible, with place names in distinct Roman lettering. Also in obedience to Ptolemy, there are no monsters, wind heads or decorative borders. Typical anomalies none the less still appear: the land-locked Indian Ocean; the small size of India and the overlarge island of Taprobane (Sri Lanka); and the horizontal stretching of the Mediterranean. A copy of this map was owned by Christopher Columbus, and it is thought that Ptolemy’s adoption of Posedonius’s measurement of the earth’s circumference, instead of the more correct and larger one of Eratosthenes, caused the hopeful mariner to underestimate the distance he would have to travel west to reach the Orient.
From 1478 (plates made) to 1490 (book printed)