Nearly 200 years ago, human blood was said to have been contained in a ceremonial tomb built within a royal palace complex in what is now Benin, according to legend. Now, an investigation into proteins found within the walls of the tomb reveals evidence that the legend is true.
According to a new study, the tomb in Abomey, once the capital of the West African kingdom of Dahomey, contains proteins that could only have come from human blood, confirming the country’s horrific history.
It is one of the first times such a discovery has been made through “paleoproteomics,” the study of protein footprints left behind in archaeological contexts.
“This discovery is important, as it provides concrete evidence of historical rituals and practices,” the biochemist Jean Armengaudan expert on ancient proteins at France’s Alternative Energies and Atomic Energy Commission, told Live Science.
Armengaud is the lead author of the new study, which was published May 29 in the journal The science of 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 lore, the tomb inside Abomey Palace Complex — built in the 19th century by King Ghezo of Dahomey, in honor of his brother, King Adandozan — used plaster that included the blood of 41 human sacrifices; 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 expeditions against the region’s powerful Yoruba state, or Oyo Empire, and thereby ended the Dahomey kingdom’s annual slave tribute.
He was considered a powerful ruler and is said to have feigned the death of his enemies to ensure his reign. According to historical accounts, the path to his hut was paved with the skulls and jaws of defeated enemies, and one of his thrones rested on the skulls of four enemy leaders.
Dahomey, now called Benin after the nearby Bay (or Bay) of Benin, is a center of the original. African Vodun or Vodou religion that took place in the Caribbean region. Traditional vodun often involves sacrifices of animal blood.
Distinguishing proteins
The researchers applied a technique called mass spectrometry together – to the proteins contained in the samples of the tomb wall, which consists of two joined round huts. The method breaks the ions into fragments to reveal their chemical structure.
Their study produced more than 10,000 matches in a protein database that identified the presence of thousands of microorganisms, as well as human and chicken blood.
“Since 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 on the wall – consistent with historical accounts, so far unverified, that blood allegedly from human sacrifices was mixed with “red oil” and holy water to make plaster .
In this case, Armengaud said, the paleoproteomic study was preferable to a paleogenomic study of ancient DNA, which could reveal 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 sacrificial victims and their origins, thereby providing a more detailed historical context.
Matthew Collinsan archaeologist at the University of Cambridge, who was not involved in the latest study, told Live Science that the research showed how proteomics could be applied to complex and challenging situations.
“If you were to use DNA, then you can tell that certain species were present – but what you can’t tell is the type of tissue that was involved,” he said. “But here you have evidence of tissue proteins associated with human blood.”