Two centuries after the French beheaded Louis XVI and dipped their handkerchiefs in his blood, scientists believe they have authenticated the remains of one such rag kept as a revolutionary relic. Researchers have been trying for years to verify a claim imprinted on an ornately decorated calabash gourd that it contains a sample of the blood of the French king guillotined in Paris on January 21, 1793. The dried, hollowed squash is adorned with portraits of revolutionary heroes and the text, "On January 21, Maximilien Bourdaloue dipped his handkerchief in the blood of Louis XVI after his decapitation". He is then believed to have placed the fabric in the gourd, and had it embellished. The sinister souvenir has been in the private hands of an Italian family for more than a century, said the team of experts from Spain and France, which published its findings in the journal Forensic Science International . Two years ago, analysis of DNA taken from blood traces found inside the ornate vegetable revealed a likely match for someone of Louis' description, including his blue eyes. But not having the DNA of any kingly relation, researchers could not prove beyond doubt that the blood belonged to Louis. That was until now, the team having managed to draw a DNA link to another gruesome artefact - a mummified head believed to belong to Louis' 16th century predecessor, Henri IV. In so doing, they provided evidence for authenticating both sets of remains - uncovering a rare genetic signature shared by two men separated by seven generations. "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. The revolution in which Louis and Queen Marie-Antoinette lost their heads in public executions also saw mobs ransack the royal chapel at Saint-Denis, which is north of Paris. Hordes hauled ancient monarchs like Henri from their tombs and mutilated the remains, which they tossed into pits. An individual was recorded to have rescued the severed head, long thought to belong to Henri, from the chaos.