On Jan 21 1793, a Parisian called Maximilien Bourdaloue witnessed Louis's public decapitation as the... "Terreur" took hold. Afterwards, he joined many others in dipping a handkerchief in the pool of blood left at the foot of the guillotine. Bourdaloue then secreted this garment inside a calabash, now in the possession of an Italian family. The rag itself has long since decomposed, but the container still carries crimson stains and an inscription recording how the souvenir was collected after the king's "decapitation". But there was no conclusive proof that the blood really belonged to Louis. A DNA sample could not solve the riddle unless it was compared with another drawn from a relative of the king.
A new study in the current issue of "Forensic Science International" has filled in the missing link. The breakthrough came when scientists took a DNA sample from the mummified head of one of Louis's most illustrious ancestors: King Henri IV, who ruled France from 1589 until 1610. This analysis established that Henri possessed a rare partial "Y" chromosome. Louis was one of his direct male-line descendants, separated by seven generations. The stains on the calabash also contained the "Y" chromosome, along with other matches, leading experts to conclude that the container almost certainly holds the blood of the executed king.
"Taking into consideration that the partial Y-chromosome profile is extremely rare in modern human databases, we concluded that both males could be paternally related," read the study. "Historically speaking, this forensic DNA data would confirm the identity of the previous Louis XVI sample." The study found "with 95 per cent confidence" that it was 246 times more likely that the owner of the mummified head and the provider of the bloodstain were related than unrelated. Both Henri and Louis came to a violent end at the hands of their subjects – and relics of both survive to this day. (Read entire article.)