Scientists have cracked one of France's most enduring mysteries, finding that a disease-ridden boy who died in a Paris prison more than 200 years ago really was the son of King Louis XVI and Marie-Antoinette and heir to the French throne.
The fate of Louis XVI's son had long intrigued France. Some historians declared the dead child to be Louis XVII. Others said the royal heir escaped and that another child died in his place to save official face during the unstable days of the French Revolution.
But now science has come to the aid of history.
Scientists from two European universities compared DNA from the heart of the dead child to DNA from hair cut from Marie-Antoinette as a child in Austria.
Philippe Delorme, the French historian who organised the tests, said the riddle finally has been laid to rest.
"It was Louis XVII. It was the last little king of France who died in the Temple prison," he said. "It's definitive."
After his parents were beheaded in 1793, Louis XVII was imprisoned in the Temple, a fortified monastery in Paris, where he died of tuberculosis aged 10, on June 8, 1795.
But until now, this official version was contradicted by rumour, legend and simple royalist hope, strengthened by some fabulous tales from that turbulent time.
Some said the body in the Temple could not have been Louis XVII, as it seemed to belong to an older child. Others claimed Louis XVII had been drugged with opium and a dead boy substituted for the living one in the coffin.
One guard at the time said he had seen many bathtubs being carried out of the prison and when the porters carrying one stumbled, he heard a child's cry from within.
But Delorme said the scientific tests were indisputable.
They were carried out by Jean-Jacques Cassiman, a professor of genetics at Belgium's Louvain University, and Ernst Brinckmann of Germany's Muenster University. Both scientists came to the same conclusion, Delorme said.
Cassiman said on Wednesday that the heart was aged between 8 and 12 years.
"(It) was extremely well-preserved. One could see all the vessels and all the compartments of the heart. But because it was mummified, we had to saw off a small piece to be able to do this analysis," he said.
Some sceptics will no doubt latch onto the heart's eventful history to throw cold water on the recent research.
The heart was stolen by the doctor who performed the autopsy on the dead child in 1795. He pickled it in alcohol for eight to ten years. One of his student's subsequently stole it, but on his deathbed, he asked his wife to return it.
After the restoration of the French monarchy in 1814, the heart was offered to various members of the royal family, but they were reluctant to accept a relic of such dubious provenance.
It finally found its way to the Spanish branch of the Bourbon family. They returned it to Paris in 1975 and it was placed in the royal crypt.
"There will always be some people who think Louis XVII escaped. But now we have indisputable scientific proof that confirms the historic proof," said Delorme, who has written "The Affair of Louis XVII."
For Delorme, the discovery is both a vindication of history and a kind of belated justice.
"For me, it's a very important day, a very moving day for a historian. It's an affair that has lasted two centuries. There have been around 800 books written on the subject and we never managed to find the response," he said.
"I think we are bestowing justice on this child. Until now, his death was stolen, it was not admitted that he died in such a horrible way," he said.