When the French people beheaded King Louis XVI on January 21, 1793, accounts from the time report that many dipped their handkerchiefs in their executed ruler’s blood. Now, two centuries after that fateful day, researchers think they’ve found one of those revolutionary souvenirs, Discovery News writes.

The hankie in question turned up two years ago when an Italian family submitted the souvenir for genetic testing. They found it stuffed within a dried, hollowed squash decorated with portraits of revolutionary heroes. The squash reads, “On January 21, Maximilien Bourdaloue dipped his handkerchief in the blood of Louis XVI after his decapitation.” Monsieur Bourdaloue likely placed the fabric within the gourd and then had it pridefully embellished.

DNA tests hinted that the blood may be authentic, since it indicates that the bleeder had blue eyes and other physical features matching up to Louis XVI’s description. But the forensics team lacked DNA from Louis or any of his family members (their bodies were mutilated and strewn about the streets after the spree of executions), so at first they could not prove definitively that the handkerchief’s stain is genuine.

However, a mummified head saved the day. The head belonged to Henri IV, who held the French throne 200 years prior to Louis’ gruesome demise. A mysterious individual rescued the severed head from the grave-ransacking chaos of the revolution, and it was passed down through the years and kept in secretive collections. A rare genetic signature preserved through seven generations and shared by the two rulers confirmed the blood’s authenticity. Discovery explains:

“This study shows that (the owners of the remains) share a genetic heritage passed on through the paternal line. They have a direct link to one another through their fathers,” French forensic pathologist Philippe Charlier said.

Genetic markers in hand, the researchers think they may be able to use the newly identified code to identify any living relatives of France’s absolute monarchs of years past.

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