Secrets of Ancient Navigators

For seafarers of the late thirteenth century, there was no GPS, no radar, and no sonar. Getting where you wanted to go depended on the skill and experience—to say nothing of daring—of your ship’s pilot. In addition, such travel often required the use of highly prized navigational charts known as “portolans” (Portolano in Italian), which provided the direction and distance to various ports in the Mediterranean. With the dawning of the so-called Age of Discovery in the early fifteenth century, portolans were treated by seafaring powers Spain and Portugal as top state secrets. Later, the Dutch and the English would use them to guide raiding and trading missions.

The portolans have long been thought by scholars to be a product of the accumulated experience of Mediterranean seamen, providing essential compass headings and distance estimates learned over generations of trial and error. Proof, however, of the actual origins of the portolan charts has been illusive, and to this day their true source remains one of the great, unsolved mysteries. And now, thanks to a new study, the plot has thickened. According to intensive Ph.D. research by geodetic scientist Roel Nicolai at Holland’s Utrecht University, the realistic sea charts of the Mediterranean and Black Sea, which first appeared in Pisa (Carta Pisano), out of nowhere, at about 1290, cannot possibly have originated in medieval Europe.

Showing the outlines of coasts, as well as ports, the charts were crisscrossed with many straight lines connecting opposite shores using the 32 directions marked on the navigator’s compass. The oldest portolans, though, strangely, make no appearance in earlier versions and reveal no logical path of development or evolution. Yet, despite the limited knowledge and measuring instruments of the period, the accuracy of the portolans is unquestioned—an astonishing fact which scholars have long attributed to fortunate coincidence. But, based on insights and methods from state-of-the-art geodesy, Nicolai’s research has now established that, even with the most forgiving assumptions, the ‘fortunate-coincidence’ hypothesis is “impossible.”


Nicolai has shown, it is not likely that the nautical compass was even available in time; and, moreover, it is also extremely unlikely that navigational methods used at that point were sophisticated enough to establish distances with such precision.

Kemo D. 7

Source: Atlantis Rising Magazine

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