Ernestine Lambriquet

Ernestine de Lambriquet (Marie-Philippine Lambriquet, 31 July 1778 – 31 December 1813) was the adopted daughter (foster child) of King Louis XVI and Queen Marie Antoinette of France. To informally allow a royal child a common playmate in this way was not an uncommon custom in early modern Europe, and Marie Antoinette considered it good for Marie Thérèse, since her daughter was known to be of a very proud disposition, in need of humility. Among the eight adopted children, however, only three (Ernestine, Armand and Zoe) actually lived with the royal family, and the rest simply lived on the queen's expense.

On the 10 August 1792, Marie Antoinette ordered the royal sub-governess Renée Suzanne de Soucy to bring Ernestine to safety. has disproved the conjecture that the Dark Countess was the true Princess Marie-Thérèse Charlotte of France.

The remains of the Dark Countess were exhumed, and bone fragments were analyzed at independent laboratories in Innsbruck, Austria, and Freiburg, Germany. Mitochondrial DNA (mtDNA) genome was sequenced. MtDNA is solely maternally inherited (mother to child) and there are numerous copies of the mtDNA genome in each human cell, making this DNA type useful for the analysis of ancient tissue samples.

Maternal genealogical lines showing relationship between Marie Therese Charlotte (daughter of Marie Antoinette) and Alexander, Prince of Saxe-Gessaphe.Princess Marie Thérèse (the presumed identity of the Dark Countess) and the living reference, Alexander, Prince of Saxe-Gessaphe, a maternal descendant of Marie Antoinette’s sister, Archduchess Maria Carolina of Austria, were compared. Although separated by six generations, the maternal inheritance of mtDNA means that there is no recombination at each generation; hence it remains the same. If the Dark Countess was truly Marie-Thérèse, the bone fragments would have had the same mtDNA profile as Alexander (whose maternal line crosses with Marie Antoinette’s mother, Maria Theresa of Austria). However, the analysis indicated that was not the case. The mtDNA profile from the Dark Countess differed significantly from Prince Alexander. Furthermore, the mtDNA of Marie Thérèse’s brother (Louis-Charles) determined in a previous study matched that of Prince Alexander, as expected, but differed from the Dark Countess.