Almost 200 years ago, human blood is said to have been incorporated into a ceremonial tomb built in a royal palace complex in what is now Benin, according to legend. Now, an investigation of proteins found in the walls of the tomb reveals evidence that the legend is true.
A tomb in Abomey, once the capital of the West African kingdom of Dahomey, contains proteins that could only have come from human blood, according to a new study, confirming the site’s gruesome history.
It is one of the first times such a discovery has been made through “paleoproteomics,” the study of trace proteins left in archaeological contexts.
“This discovery is important because it provides concrete evidence of historical rituals and practices,” biochem Jean Armengaudan expert on ancient proteins from the French Commission for Alternative Energies and Atomic Energy, told Live Science.
Armengaud is the lead author of the new study, which was published May 29 in the journal Proteomics. He and his colleagues examined samples taken from the tomb between 2018 and 2022 during excavations at the site by archaeologists from France and Benin.
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According to local tradition, the tomb is inside Abomey Palace Complex — built in the 19th century by King Ghezo of Dahomey in honor of his brother King Adandozan — used plaster that contained the blood of 41 human victims; 41 was considered a sacred number, the authors wrote in the study.
King of Dahomey
Ghezo, who ruled from 1818 to 1858, famously led several military campaigns against the powerful Yoruba state in the region, or the Oyo kingdom, ending the annual slave tribute of the kingdom of Dahomey.
He was considered a powerful ruler and was said to stage the death of his enemies to secure his rule. According to historical accounts, the path to his hut was paved with the skulls and jaws of defeated enemies, and one of his thrones stood on the skulls of four enemy leaders.
Dahomey, now called Benin after a nearby bay (or bay) in Benin, is the center of the original The African religion of vodun or vodou which was developed in the Caribbean region. Traditional Vodun often feature sacrifices of animal blood.
Prominent proteins
The researchers used a technique called tandem mass spectrometry — to proteins contained in samples of the wall of the tomb, which consists of two round huts joined together. The method breaks the ions into fragments to reveal their chemical structure.
Their study yielded more than 10,000 matches in a database of proteins that identified the presence of thousands of microorganisms as well as human and chicken blood.
“Because proteins are more stable molecules compared to DNA, paleoproteomics can provide extensive information about the organisms that produced these proteins in ancient times,” said Armengaud.
The results clearly show that human blood was one of the substances in the wall – in line with historical accounts, never verified before, which claimed that blood from human sacrifices was mixed with “red oil” and holy water to make the plaster.
In this case, Armengaud said, a paleoproteomic study was preferable to a paleogenomic study with ancient DNA, which could detect genetic material from individuals such as the people who built the structure without determining how they were involved.
But paleoproteomics and paleogenomics can also complement each other. Armengaud hopes that DNA sequencing of samples from the Abomey tomb can identify the number of victims and their origins, thereby providing a more detailed historical context.
Matthew Collinsan archaeologist from the University of Cambridge who was not involved in the latest study told Live Science that the research showed how proteomics can be used in complex and challenging situations.
“If you used DNA, you could say that certain species were present – but what you couldn’t determine was the type of tissues that were involved,” he said. “But here you have evidence of tissue proteins associated with human blood.