A Geologist Kicked a Rock—Or So He Thought. It Led Him to One of the World’s Richest Shipwrecks.

4 min readHere’s what you’ll learn when you read this story:Wrecked in 1533, the Bom Jesus is the oldest and richest shipwreck ever discovered along the sub-Saharan African coast.Located in what’s called the “forbidden zone” near a remote diamond mine, performing a rescue excavation of the ship proved extremely difficult. Nearly two decades after its discovery, some artifacts are still deteriorating in long-term storage.On March 7, 1533, a Portuguese three-masted carrack (also known as a Nau) called the Bom Jesus, or “Good Jesus,” sailed down the Tagus River, wound its way through Lisbon, and slipped out into the Atlantic on its 15-month journey to gather spices from faraway lands. Some 300 souls were aboard, including sailors, soldiers, enslaved people, merchants, priests, and the captain, Dom Francisco de Noronha.As the ship’s mast finally dipped below the horizon, those on shore likely had high hopes for the returning wealth this voyage promised, but the vessel never returned. Instead, the Bom Jesus became one of 21 ships known to have been lost on the outbound run to India between 1525 and 1600, and the only one to go down anywhere near present-day Namibia. After nearly 500 years, the ship faded from memory. But then in 2008, a company geologist at a diamond-mining venture called Namdeb, which is jointly owned by De Beers and the Namibian government, came across a strange, roughly circular rock in the sand.As it turned out, this wasn’t a rock at all, but rather a copper ingot bearing the insignia of a trident, a known mark of Anton Fugger—one of Europe’s wealthiest merchants. From what archaeologists and historians could piece together, the Bom Jesus drifted dangerously close to the coast during a storm, smashed into a rock, and scattered along the coast about 16 miles north of the mouth of the Orange River, near the present-day diamond mining town of Oranjemund.Amy Toensing//Getty ImagesAerial view of the shipwreck site and the seawall built to keep the wreck site dry in the Namdeb diamond mine in Oranjemund, NamibiaMeticulous excavation work recovered 22 tons of these ingots, according to National Geographic, along with other sumptuous artifacts of the era, including ivory, gold, and astrolabes—most of which were encased in lime and sandy concretions that had protected them from the elements over the centuries. Not only was the Bom Jesus the oldest shipwreck ever found in this part of the world, it was also the richest. Apart from a few toe bones still inside a shoe, no human remains were recovered, which leads archaeologists to suspect that many, and perhaps most, of those aboard made it to land.Amy Toensing//Getty ImagesIvory tusks excavated from the wreck of the Bom JesusWhile its initial discovery was immensely lucky, the hard work was just beginning, because rescue excavation of the extraordinary shipwreck was far from simple. The area containing the diamond mine in Oranjemund, Namibia, is a heavily restricted area known as the Sperrgebiet, German for the “Forbidden Zone.” While that ominous designation protects the ship from would-be plunderers, the various jurisdictions overlapping in the Sperrgebiet caused more than a bit of confusion about how to proceed with the excavation.A new study analyzing this excavation published in the International Journal of Historical Archaeology observes that the initial response was carried out by diamond mine workers with no maritime archaeologist on site (though one provided guidance on the telephone). The submerged artifacts themselves also represented additional challenges, as items brought into an oxygenated environment rapidly deteriorated.“Maritime artifacts present distinct conservation challenges based on their material composition and the duration and conditions of submergence,” the authors write. “For metal artifacts, the transition from anaerobic underwater environments to oxygen-rich atmospheric conditions triggers electrochemical reactions that can rapidly destroy archaeological evidence.”After painstaking desalination efforts, long-term storage of the artifacts inflicted additional degradation. For example, photographic evidence of the Fugger trident stamps on the ingots, which were relatively prominent when exhumed in 2008, deteriorated by 2018 and are now much less visible. And while facilities exist to slow this deterioration, none are currently available, and funding for the preservation of the Bom Jesus treasures remains unstable at best.“When I started, the artifacts were just sitting there collecting dust. They were deteriorating at a fast pace because there was no proper storage,” an unnamed technician associated with the project said as part of the study. “It was basically an open workshop, with dust everywhere, no climate control, no security to speak of.”Rescue excavation is notoriously difficult and such struggles are not unique to this particular Namibian operation. In fact, the authors make note of many individuals who worked tirelessly to protect this archaeological find. Their hope is that by revisiting some of the mistakes and hardships faced by the Bom Jesus excavation, future projects will endeavor to learn from those mishaps and better protect the next priceless artifacts that currently lie beneath our feet.Darren lives in Portland, has a cat, and writes/edits about sci-fi and how our world works. You can find his previous stuff at Gizmodo and Paste if you look hard enough.