I just finished reading the book, "The Lost King of France, How DNA Solved the Mystery of the Murdered Son of Louis XVI and Marie-Antoinette" by Deborah Cadbury. Very interesting. Marie-Antoinette was sent to the guillotene in 1793. Louis the XVI had already been beheaded. Eventually, the King's sister was also sent to the guillotene. The surviving children of Louis the XVI and Marie-Antoinette had been imprisoned in the Temple Tower (built by the Knights Templar) along with their parents. The future King Louis XVII (Louis-Charles) was separated from his sister Marie-Therese. He never knew his mother was killed. He was a little boy of 8 and was left by himself in a dark, dank prison. He was treated very poorly and eventually he died. (possibly TB) Marie-Therese was eventually freed and stories that her brother's was smuggled out of the prison were heard more and more. Many fake Louis XVIIs tried to wheedle their way into the royal family and kept Marie-Therese guessing up until she died in her 70's. She never agreed to meet with any of the fakers. A few of the want-to-be Louis' had followers who backed their claims and tried to push for their acceptance as the real Louis XVII. In 1846 the grave of the child from the Tower was opened and the bones inspected by doctors. The bones did not fit the size of an 8 year old boy. In the late 1890's, the bones were looked at again with the same outcome as the 1846 inspection. In the 1940's a Dr. Locard was doing early forensic testing regarding trace evidence. He tested some hair samples. In 1999 at the beginning of the use of mitochondrial DNA, samples of hair from Marie-Antoinette's sisters was collected along with some from Marie-Antoinette. Also DNA samples from descendants of the Habsburg family were tested. These tests tended to eliminate a Mr. Naundorff who 200 years before had claimed to be Louis XVII. His descendants still believed they were part of the royal line. But...thanks to a doctor who stole the little boys heart during the autopsy at the prison ( in June 1795) and tried to preserve it for the family, the truth was found. (French Kings' hearts were buried in the family tomb). The heart was all dried up and had been entrusted from family to family for the past 200 years. Finally this heart was tracked down and tested. The mitochondrial DNA matched that of the Habsburg descendants. It matched closely to that of Marie-Antoinette and her sisters, but it was determined that a full set of markers were not captured because of the age of the hair. Another attempt at matching hair from Marie-Antoinette's sister brought positive results. So, the little boy in the Temple prison did not escape. King Louis XVII had died at the age of 10 in the Temple prison.
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