Researchers cast new light on old map

Ptolemy's maps depicted a world that was round (Swiss National Science Foundation) Ptolemy's Geography

This week saw the launch in Switzerland of a new edition of a book that inspired Christopher Columbus and helped revolutionise the art of map-making.

When Columbus was pondering how to reach Cathay, he had in his hands a world map drawn by the first century Greek geographer Ptolemy – a map which showed clearly that the world was round.

The edition of Ptolemy’s Geography is the work of an international team of researchers led by Bern University professors Alfred Stückelberger and Gerd Grasshoff.

They were given unique access to possibly the oldest existing copy of the work, preserved in the Topkapi museum in Istanbul. It was in such poor condition that it took the team, backed by the Swiss embassy, two years of negotiation with the Turkish authorities before they gained permission to study it.

“It was a most exciting experience to have this book in our hands, and to be allowed to photograph every page,” Stückelberger told swissinfo.

Using this manuscript and other copies from the Vatican, Venice, Florence and Paris they have produced the first complete modern edition of the Greek original, and the first full German translation.

It wasn’t always easy, even for Stückelberger as an expert on classical Greek science. “Ptolemy’s thought was razor-sharp, but his sentences are long and complex. I sometimes had to ponder for hours, or even days, to tease out exactly what he meant,” he admitted.

Ptolemy, who was born in Alexandria in Egypt in around 100AD, was an astronomer, mathematician and geographer.

Body of knowledge

He wrote his Geography to sum up existing knowledge of the subject, but he took it further than anyone before him. He was the first person to use the system of longitude and latitude as we know it today.

The book begins with an introduction to the science of mapmaking, including the problem of how to project a curved surface onto a plane.

It then presents a catalogue of names with the coordinates (longitude and latitude) of some 6,000 places, which Ptolemy drew up using information gathered from sailors, merchants and the Roman military archives. In Switzerland the list includes the names of the important Roman towns now known as Avenches, Nyon and Martigny.

The last section of the book contains a map of the world, drawn according to Ptolemy’s instructions, stretching from the Canaries to eastern China, and from just south of the equator to southern Scandinavia. This is supplemented by 26 country maps.

Ptolemy wrote for specialists and few copies of his books were made. His important work on astronomy was preserved by the Arabs and knowledge of it trickled back into mediaeval Europe; but such was European ignorance about Ptolemy himself that he was sometimes confused with the kings of Egypt of the same name.

Western Europe learnt about his Geography in the 14th century, thanks to copies made in Byzantium around 1300, some of which found their way to Italy.

The discovery of Ptolemy shattered the mediaeval world view; his work was soon translated into Latin, and gained a further boost with the arrival of printing. All this just as European nations were on the point of embarking on their voyages of discovery.

Despite Ptolemy’s great historical importance, the new Swiss edition is the first complete Greek text since a now outdated version published in the 1840s.

“I realised this was a gap that absolutely had to be filled,” Stückelberger explained.

The researchers even managed to correct some of the mistakes in the old versions. Not surprisingly, numerous errors had crept in over the centuries.

The new book should help rekindle interest in Ptolemy and restore his reputation as a man of genius. He may not have been a king of Egypt, but he was a prince among scientists.

swissinfo, Julia Slater

Key facts

A Swiss-led team has produced the first full German translation of Ptolemy’s Geography, a full Greek version and new maps, plus a database on CD-Rom.
The project was supported by the Swiss National Science Foundation.
The book, Klaudios Ptolemaios Handbuch der Geographie, is published by Schwabe AG of Basel in two volumes + CD-Rom (ISBN 3-7965-2148-7; SFr250/€170)