A 16th-century Run for Gold and for… an Accurate Nautical Rutter?

In March 1569, King Sebastian ordered Francisco Barreto to head his fleet from Lisbon to Eastern Africa to conquer the famous Mutapian gold mines (a goal that was not achieved). However, the Portuguese King also wanted Barreto’s expedition to solve another problem: the previous Portuguese shipwrecks in the East African coast.

After arriving to Mozambique in 1570-71, Barreto sent a nobleman to “discover” the coast between Mozambique and the Cape of Good Hope. The unfortunate nobleman prepared a nautical rutter, but perished in the area due to its several dangers. King Sebastian did not receive his rutter, and some years later he ordered Manuel Mesquita Perestrelo to produce a nautical rutter of the area. This time the King’s choice felt upon a nobleman that had been a victim of a famous shipwreck in the region during the 1550s and who had even written a report about it. As a result, Perestrelo wrote an important nautical rutter dedicated to King Sebastian. In this rutter, Perestrelo detailed all the coastal signs and explained how to anchor with success in good and bad places. He also described all the occasions in which he was about to die, in spite of all his experience. His rutter was so technically accurate that even during the 17th and 18th centuries, French, English and Dutch seafarers used it as the reference for the dangerous navigation on the region.

Perestrelo’s rutter is, thus, a testimony that good nautical rutters were always required to avoid the many dangers of an Oceanic voyage. King Sebastian also knew that good nautical rutters could help to prevent shipwrecks and guarantee the financial revenues of his Crown. Perestrelo’s story also shows that in the 16th century, nautical science was far from being a fixed matter; it always required adaptions. The multiple global impacts of maritime expansion explain how a document that today seems to us of a boring technicality (a nautical rutter) could become the focus of attention of different society echelons: from the pilot, the merchant, the missionary, the nobleman, the ambassador, to a King. This raises an intriguing question: Is it possible that nautical rutters made a very particular and unique contribution to the scientific development of Europe in the 16th and 17th centuries? [Nuno Vila-Santa]