The ship was laden with tons of copper ingots, elephant tusks, gold coins — and cannons to fend off pirates.
But it had nothing to protect it from the fierce weather off a particularly bleak stretch of inhospitable African coast, and it sank 500 years ago.
Now it has been found, stumbled upon by De Beers geologists prospecting for diamonds off Namibia.
"If you're mining on the coast, sooner or later you'll find a wreck," archaeologist Dieter Noli said in an interview Thursday.
Namdeb Diamond Corp., a joint venture of the government of Namibia and De Beers, first reported the April 1 find in a statement Wednesday, and planned a news conference in the Namibian capital next week.
The company had cleared and drained a stretch of seabed, building an earthen wall to keep the water out so geologists could work. Noli said one of the geologists saw a few ingots, but had no idea what they were. Then the team found what looked like cannon barrels.
The geologists stopped the brutal earth-moving work of searching for diamonds and sent photos to Noli, who had done research in the Namibian desert since the mid-1980s and has advised De Beers since 1996 on the archaeological impact of its operations in Namibia.
The find "was what I'd been waiting for, for 20 years," Noli said. "Understandably, I was pretty excited. I still am."