Ptolemy's locations in Germania identified

A group of classical philologists, mathematical historians and surveying experts at Berlin Technical University's Department for Geodesy and Geoinformation Science has produced an astonishing map of central Europe as it was 2,000 years ago.

The map shows that both the North and Baltic Seas were known as the "Germanic Ocean" and the Franconian Forest in northern Bavaria was "Sudeti Montes." The map indicates three "Saxons' islands" off the Frisian coast in northwestern Germany -- known today as Amrum, Föhr and Sylt...

This unusual map draws on information from the mathematician and astronomer Ptolemy, who, in 150 AD, embarked on a project to depict the entire known world. Living in Alexandria, in the shadow of its monumental lighthouse, the ancient scholar drew 26 maps in colored ink on dried animal skins -- a Google Earth of the ancient world, if you will...

Ptolemy demonstrated extensive knowledge of this remote area, indicating the locations of mountains, rivers and islands. An index lists 94 "poleis," or cities, noting their latitude and longitude accurately to within a few minutes...

Yet the data the ancient geographer used is distorted. Errors of scale crept in as he transcribed the Earth's sphere to the flat plane of a map. Ptolemy believed the northern lands to be narrower and more elongated than they are and bent Jutland in Denmark and Schleswig-Holstein in Germany too far to the east.

Ptolemy also failed to accurately connect the different parts of his map. Mistakes worked their way in despite his attempts to locate calibration points to tie together his patchwork of geographical information. The inevitable result was confusion.

Linguists and historians have tried repeatedly to decode the yellowed document -- in vain. Among researchers, it came to be known as an "enchanted castle," a mystery no one could crack. Access to Germany's prehistory was believed closed off forever...

The Berlin-based team pored over the recalcitrant data for six years, working together to develop a so-called "geodetic deformation analysis" that would help to correct the map's mistakes...

But the team of experts in Berlin had the great fortune to be able to refer to a parchment tracked down at Topkapi Palace in Istanbul, Turkey, the former residence of the Ottoman sultans. The document, consisting of unbound sheepskin pages with writing in Roman capital letters, is the oldest edition of Ptolemy's work ever discovered. A reproduction of this version is due to be published next year...

The new map suggests that minor German towns such as Salzkotten or Lalendorf have existed for at least 2,000 years. "Treva," located at the confluence of the Elbe and Alster Rivers, was the precursor to Hamburg; Leipzig was known as "Aregelia."

All this offers up rather exciting prospects, since it makes half the cities in Germany suddenly 1,000 years older than previously believed... Archaeological interest in the map will likely be correspondingly large...

The rest of the story is at Der Spiegel.