The DNA sample used to positively identify the remains of the two previously unaccounted for Romanov children, bringing to a close an almost century-long mystery about the fates of the Russian royal family, came from this present-day European royal:

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The matrilineally-inherited mitochondrial DNA (mDNA) of the United Kingdom's Prince Philip was used in 2008 to confirm the identities of two sets of remains believed to be the missing members of the Romanov family. In 1918, recently abdicated Russian Tsar Nicholas II was executed by Bolshevik revolutionaries, along with his wife Alexandra, their five children, and several servants. Rumors persisted throughout the 20th century that one or two children - namely Grand Duchess Anastasia and possibly Tsarevich Alexei - survived the attack and lived-on under assumed identities. In 1991, the remains of Nicholas, Alexandra, three of the children and some servants were located, leaving two children unaccounted for. In 2007, a second gravesite was discovered in the same area, containing the remains of two children who matched the ages and genders of the Romanov children missing from the rest of the family's mass grave. Philip is the great-nephew of Tsarina Alexandra Romanov, and has the same mDNA the Romanovs would have had. His DNA was also used to identify the remains in 1991. The tests revealed that all seven of the imperial family members were in fact executed in 1918, ending the decades-long speculation.

The DNA Sample Used to Positively Identify the Remains of the Two