Kaspar Hauser, shown here in a undated portrait based on a painting by Johann Friedrich Carl Kreul, appeared seemingly out of nowhere at about age 16 in what's now Nuremberg, Germany, in May 1828. A fantastic story that he was a kidnapped prince soon took root.

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“His birth was unknown, his death hidden.”

So reads the headstone (translated from Latin) marking the grave of the enigmatic man known as Kaspar Hauser, who died in 1833. Nearly 200 years later, scientists have finally solved a longstanding mystery about Hauser’s suspected ties to German royalty.

Hauser appeared seemingly out of nowhere in what is now Nuremberg, Germany, on May 26, 1828, when he was about 16 years old. He was found wandering the town square with no identification and with an unsigned letter clutched in his hand.

The letter and Hauser’s fragmented recollections told a harrowing tale: that he grew up in a cramped dungeon that he never left and was fed and kept clean by a benefactor whom he never saw. When the teenage Hauser turned up in the town center, he could barely write his own name and was scarcely able to communicate with officials who questioned him.

A fantastic story took root, suggesting that Hauser was a kidnapped prince of local lore, taken from the royal family of Baden, then a sovereign state in what’s now southwest Germany. There was no evidence to support this theory, but the rumors persisted, endearing Hauser to fashionable members of European society and establishing him as a local celebrity.

Long after Hauser’s death, scholars searched in vain for any proof of regal parentage. In the mid-1990s, genetic data from samples of Hauser’s preserved blood suggested that he was not part of the Baden lineage. But these results were soon contradicted by tests a few years later that sampled Hauser’s hair.

A study of plums, rosebuds and cherries by Hauser (from 1833), a watercolor with largely spotted stenciling, appeared in the temporary exhibition "Kaspar Hauser — Pictorial World. Known and Unknown Drawings" at the Markgrafen Museum in Ansbach, Germany, in 2016.

Recently, scientists found definitive answers through new analysis of hair samples from Hauser, according to research published in the journal iScience. Their approach, developed for ancient fragments of DNA from Neanderthals, was more sensitive than earlier methods.

When they analyzed Hauser’s mitochondrial DNA, or mtDNA — genetic code passed down on the maternal side — they confirmed that it didn’t match mtDNA from Baden family members. Nearly two centuries after Hauser’s mysterious appearance, this finding ruled out the possibility that he was a kidnapped prince.

The new analysis “exemplifies how molecular genetics can unravel historical mysteries,” said Dr. Dmitry Temiakov, a professor in the department of biochemistry and molecular biology at Thomas Jefferson University in Philadelphia.

“This is a very comprehensive study,” said Temiakov, who was not involved in the research. “(It) accounted for all previous data, examined and explained the discrepancies in DNA sequencing analyses that took place at different times and were performed by different methods, presented new data, and carefully estimated the probability of an individual matching a particular lineage.”

Unraveling DNA

The lab that conducted the new analysis has worked for nearly two decades to improve techniques for studying highly degraded DNA, said lead study author and forensic molecular biologist Dr. Walther Parson, a researcher at the National DNA Database Laboratory of the Austrian Federal Ministry of the Interior in Innsbruck, Austria.

For their study, the scientists first reviewed earlier findings about Hauser. In 1996, a lab in Munich, Germany, analyzed blood from Hauser’s underwear. (He died of a knife wound, and his bloodstained clothes are preserved in a museum in Ansbach, Germany.) According to the Munich lab, mtDNA in Hauser’s blood didn’t match Baden mtDNA. However, some researchers who supported the “lost prince” hypothesis claimed that the blood may not have belonged to Hauser, Parson told CNN.

“It has been said that the curators of the museum where the trousers of Kaspar Hauser were put on display, that they would renew the bloodstain in order to make it look better,” adding fresh blood from a different source, he said. “If that was the case, the new blood would mask the old blood and would very likely have different mitochondrial DNA.”

In the early 2000s, another lab in Münster, Germany, tested hair samples from Hauser. Those results showed that Hauser’s mtDNA was a close match to that of the Badens, contradicting the findings from Munich.

“They were in a stalemate,” Parson said.

A royal hoax debunked

Parson’s lab conducted new analysis of Hauser’s hair, using strands collected before and after his death. The hairs were documented extensively and could be authenticated with more certainty than the blood samples, Parson said. What’s more, the lab’s highly sensitive technique enabled researchers to be sure that they were sampling the hair shafts, where the useful mtDNA was located, and that the samples weren’t contaminated.

“With the improved sequencing method, we were able to get sequences of the highly degraded component,” delivering results with a much stronger signal than in the previous hair analysis, Parson said. The new results matched those of the blood analysis from 1996, finding that Hauser’s mitotype — a set of mitochondrial alleles for different genes — was type W. The mitotype of the Badens was type H.

“That changes the picture, because now the hair samples give the same result as the blood sample,” Parson said.

To confirm their results, the researchers sent hair strands to a third lab — in Potsdam, Germany — that specialized in ancient DNA but did not tell scientists there that the sample was Hauser’s hair. The Potsdam blind analysis also returned the type W mitotype for the Hauser sample.

“The consistency of data across three independent laboratories further reinforces the study’s conclusions,” Temiakov added.

‘The riddle of his time’

According to the “prince theory,” Hauser’s parents were the Grand Duke Carl and Grand Duchess Stéphanie de Beauharnais. The grand duchess gave birth to a son on September 29, 1812, and the unnamed child died when he was 18 days old.

However, some whispered that the deceased infant was another baby, swapped for the 2-week-old prince by his step-grandmother, Countess Louise Caroline von Hochberg. The theory goes that the real prince — the man who later called himself Kaspar Hauser — was then hidden away. When Carl and Stéphanie subsequently failed to produce a male heir, one of Countess Hochberg’s sons ascended the grand ducal throne.

The new findings about Hauser not only debunk the prince theory; they also demonstrate the importance of pushing the limits of technologies for DNA analysis, Parson said. “That, of course, has an impact on how we continue to work on mitochondrial DNA in human identification cases in forensics,” he added.

But if Hauser wasn’t a “lost prince,” who was he? It’s impossible to tell from the mtDNA evidence, which could only associate him with a Western European lineage, according to the study.

In the Ansbach cemetery where Hauser is buried, his tombstone describes him as “the riddle of his time.” Whoever Hauser was, however, is a riddle that is yet to be solved.

Mindy Weisberger is a science writer and media producer whose work has appeared in Live Science, Scientific American and How It Works magazine.