In late December 1794, the Portuguese ship São José-Paquete de Africa found itself caught in a storm rounding the southern tip of the African continent. Seeking protection from the fierce winds the ship hugged the coastline, but this was ultimately its undoing, as the São José crashed into a submerged reef and broke apart in a matter of hours.
The captain and all his crew survived the shipwreck, but 212 slaves perished – roughly half the number of people who had been packed into the São José at Mozambique 24 days earlier.
Historians and archaeologists from around the world have been working quietly since 2010 recovering artifacts from the São José, after a years-long search to identify the ship and its cargo. The discovery will be announced at a ceremony in Cape Town, South Africa, Tuesday and various artifacts from the ship will be displayed in museums around the world over the coming months.
Some of the artifacts are destined for the Smithsonian's National Museum of African American History and Culture, which will open on the National Mall in the fall of 2016.
The São José is believed to be the first slave ship ever discovered that wrecked while carrying slaves.
"They have found ships that were once slave ships but didn’t sink on the voyage. This is the first ship that we know of that actually sank with enslaved people on it," said Lonnie Bunch, the founding director of the museum, in an interview with the Smithsonian Magazine.
The wreckage was first discovered by treasure hunters in the 1980s, who misidentified it as the Dutch merchant ship Schuleynburg, which had sunk in 1756. The divers had to report their findings to the South African government, per the regulations at the time, and this alerted historians from around the world to the ship's existence.
But the true history of the ship – and the cargo it had been carrying – wasn't confirmed until just a few years ago.
The discovery was led by the Slave Wrecks Project, a coalition of researchers from George Washington University, the Iziko Museums of South Africa, the South African Heritage Resource Agency, the US National Park Service, and others. Divers have been quietly excavating the wreckage – which lies barely 100 meters from the South African coast, near Cape Town – since 2010. Their work had to be kept secret, they said, so more treasure hunters wouldn't come to the site.
That year divers found copper fastenings and copper sheathing in the wreckage, artifacts that hadn't come into common use on ships until the late 18th century, meaning it couldn't be the Schuylenburg.
The biggest clue, however, was the discovery of iron blocks in the wreckage. Jaco Boshoff, a maritime archaeologist with the Iziko Museum, found the blocks himself in 2012. He said he "knew immediately" the significance of the find, according to The New York Times.
The blocks were used at the time as ballast to counterbalance the variable weight of human cargo, which can shift up and down over the course of a long Atlantic voyage as some slaves die and others experience weight fluctuations. The more living cargo a ship carries, the more ballast it needs.
"That people were calculating the weight of human bodies that way – it’s difficult to imagine," said Stephen Lubkemann, an associate professor at George Washington University and a member of the Slave Wrecks Project.
By 2012, researchers for the Slave Wrecks Project had found the São José's manifest, which detailed the ship's departure from Lisbon to Mozambique. According to the manifest, the ship had left Europe with 1,500 iron blocks of ballast destined for Mozambique, a relatively new market compared with the West African coast, which slave traders had been visiting for centuries. The ship left Mozambique Island with between 400 and 500 slaves, according to records from the time, and was destined for Maranhão on the Brazilian coast. The voyage ultimately lasted 24 days.
"The Sao Jose slave shipwreck site reverberates with historical significance and represents an addition to our underwater heritage that has the potential to advance knowledge and understanding of slavery, not only at the Cape but on a global level," said Rooksana Omar, CEO of Iziko Museums, in a statement.
The ship was so close to shore it was able to fire off a cannon blast to signal for help. During a court inquest into the wreck – discovered by researchers in 2011 – the ship's captain, Manuel Joao Perreira, described the ship being torn apart in the turbulent coastal waters. The captain and crew worked to save as many slaves as they could. Some were able to reach the shore on a barge, but the fierce weather prevented the barge from returning, he testified.
In all, some 212 slaves died. Two days later, the surviving Africans were resold into slavery in the Western Cape.
The press conference on Tuesday will be preceded by a memorial ceremony, for both the people who perished in the shipwreck and those who were resold into slavery afterward. Divers will also place soil from Mozambique Island on the underwater site, memorializing those who drowned and representing their last footfall on the continent before the São José went down.
"We hope to bring the memory of those enslaved Africans back into consciousness,” said Paul Gardullo, historian and curator at the Smithsonian African-American museum, in an interview with Smithsonian Magazine.
Bunch, who will attend tomorrow's ceremony, said there is likely still more to find at the site. The turbulent surf that helped sink the São José has complicated the recovery process, researchers say. The waters are so rough divers said working on the site was like working in a washing machine. Some objects were buried six to eight feet under the sand. Items would be uncovered, documented, and then covered over by sand again just a few hours later.
The artifacts – which will include some of the iron blocks used as ballast – will be on a 10-year loan to the African-American museum, according to the Smithsonian Magazine. The museum, he added, will be part exhibition, part memorial, to "help people get a better understanding of the slave trade."
"It’s really a place where you can go and bow your head, and think about all those who experienced the middle passage, all those who were lost," said Bunch. "It’s both a scholarly moment, but also, for many people, it will be a highly personal moment."
Kamau Sadiki, vice president for the National Association of Black SCUBA Divers, who worked with the Slave Wrecks Project, described his experience as "extremely emotional [and] humbling."
"Just to be able to dive that site, to find a tangible piece of artifact, or information, something to raise their silent voices, to tell their story, is an extraordinary thing," he said on a video on the Slave Wrecks Project web site.