The fate of Louis XVII of France, a royal heir lost in the blood and flames of revolution, has been one of Europe's most intriguing and enduring historical mysteries, spawning hundreds of books and dozens of pretenders to the French throne for more than two centuries.

The mystery finally ended today: DNA analysis confirmed that the heart of the young king rests in a crystal globe in a basilica in a suburb of Paris. Experts said that the evidence provided by the telltale heart offers scientific proof that Louis-Charles, the son of King Louis XVI and Queen Marie-Antoinette, both guillotined during the French Revolution, died shortly thereafter at the age of 10, ending a theoretical two-year reign as Louis XVII.

The announcement by historians and scientists commissioned by the keeper of France's royal relics, ended decades of rumors and suspicion--even in this very republican land--that a Bourbon ruler of France might live to claim the throne. Prince Louis de Bourbon, Duke of Anjou, a 26-year-old blue-blood and the closest living relative to Louis-Charles, flew in from Spain for the announcement. He graciously dedicated the discovery to "the memory of an innocent child who was a victim of history."

The heart that reposes at the basilica in St. Denis with other royal remains and relics has always been said to be that of the young king, who died of tuberculosis two years after the execution of his parents at what is now the Place de la Concorde, at the southern end of the Champs Elysees. But there has never been any proof. Over the years, one pretender after another has sprung up to claim that Louis XVII--he technically became king following the death of his father in 1793--was spirited away alive and a body of another child left in his place.

"I knew five respectable people who were convinced they were members of the royal family," said the Duke of Bauffrement, France's custodian of relics and the man who commissioned the DNA investigation. "Three of them were completely crazy, but two were very solid." Some pretenders go back centuries. One, Karl Wilhelm Naundorff, was buried in 1845 in Holland with the epitaph: "Here lies Louis XVII, King of France." DNA analysis later disproved his claim.

The case was another example of how history has become science. Documents can lie, but DNA analysis, properly employed, cannot. DNA, or genetic coding, has been used to discredit a woman who claimed for years that she was Grand Duchess Anastasia, daughter of Czar Nicholas II, who was executed with his family by Bolshevik gunmen in July 1918. It was also employed recently to show that Thomas Jefferson probably fathered children by a slave. Just today, French authorities said they will use DNA analysis on stamps licked by an anonymous writer of mysterious notes in the death of a young boy 16 years ago.

Scientific identification of the heart of Louis-Charles was no more amazing, however, than the documentary record of its turbulent passage through the last 205 years. Historian Philippe Delorme, who laid out the tale for reporters, called it "a miraculous and almost providential adventure."

After Louis XVI and his queen were guillotined, the new king and his older sister, Marie-Therese, were confined to the dungeon of the Temple prison in Paris. Jailed in solitary darkness in a filthy cell, the boy contracted tuberculosis and died on June 8, 1795, in the arms of his guardian. His death certificate called him "Louis-Charles Capet," his family name.

His physician, Philippe-Jean Pelletan, performed an autopsy the next day. By his own admission in a handwritten document, copies of which were distributed to reporters today, Pelletan secretly took the heart, "wrapped it in a handkerchief and put it in my pocket without being seen." He kept it in a glass case on his bookshelf, originally preserved in alcohol, which later dried up.

In 1810, the heart was stolen by a student, Jean-Henri Tillos, in whom Pelletan had confided, Delorme said. Tillos then contracted tuberculosis and, repenting on his deathbed, told his wife what he had done. She returned the heart to Pelletan, and, in 1828, the dedicated doctor turned it over to the archbishop of Paris.

The prelate kept it until the Revolution of 1830, when citizens again flooded the streets of Paris and raided the archbishop's residence. According to Delorme, a blue-collar worker identified as B. Lescroart knew the story of the heart and tried to protect it from the mob so he could restore it to the Pelletan family. But another revolutionary grabbed the crystal case, a struggle ensued, the case shattered and the heart was lost.

Days later, Lescroart and Pelletan's son returned to the archbishop's residence to search for the heart. They found the crystal shards, and then the heart itself, buried in a pile of sand in the courtyard. Eventually, the heart was presented to a representative of the Bourbon heirs of France, but by this time the Orleans branch of the family had assumed and lost the throne, and France had become a republic. In 1975, the heart was presented to the basilica of St. Denis to lie with other royal relics.

The Duke of Bauffrement, who said he has been trying to authenticate the heart since 1946, instigated the scientific inquiry because "before, it was just my personal opinion."

For the DNA test, five pieces of the organ--four from the heart wall and one from the aorta--were removed in a ceremony at St. Denis in December. The samples were divided and sent to two different labs, one in Belgium, the other in Germany. Scientists there, they explained today, first had to determine whether the mitochondrial DNA could be analyzed, then to make sure it was consistent.

Finally, the scientists explained, they matched it with DNA from presumptive relatives of Louis-Charles, both living and dead. They were given hair samples from Marie-Antoinette and her two sisters, which had been preserved in lockets, while two living descendants of the sisters, Queen Anna of Romania and her brother, Andre of Bourbon-Parma, donated tissue samples for comparison. In fact, science could not entirely solve the mystery. The analysis confirmed only that the heart is that of a relative of Marie-Antoinette and her relatives. As chief scientist Jean-Jacques Cassiman put it: "It is up to historians to determine whether it is [that of] Louis XVII."

There are, however, no other candidates. The heart of Louis-Charles's older brother, who died in 1789, also has been preserved, but scientists say it could not be mistaken for that of the young king because its condition is inconsistent with the turbulent circumstances of his death and his heart's wayward history.