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It is generally thought that Bram Stoker based the character Count Dracula on the historical figure Vlad the Impaler. Vlad was from a Romanian noble family known as the House of Draculesti and was Voivode (Duke) of Wallachia. He was known for being extremely cruel and fond of brutal, bloody punishments. He earned his nickname because he would often have his enemies impaled.
The British Royal Family is not directly descended from Vlad the Impaler but they are however descended from his brother, Vlad the Monk. The above chart shows how. You can also watch the following video for the complete explanation:
Here's the complete line:
Vlad Dracul (d. 1447)
Vlad the Monk (1431-1495)
Radu the Great (1495-1508)
Mircea the Shepherd (1479-1560)
Princess Stanca Basarab (1518-1601)
Zamphira Logofat de Szazsebes (d. 1602)
Adam Racz de Galgo
Peter Racz de Galgo (1583-1672)
Christina Racz de Galgo
Catherine Kuun de Osdola
Ágnes Kendeffy de Malmoviz (b. 1727)
Baron Gregor, Inczédy de Nagy-Várad (d. 1816)
Baroness Ágnes Inczédy de Nagy-Várad (1788-1856)
Countess Claudine Rhédey von Kis-Rhéde (1812-1841)
Francis, Duke of Teck (1837–1900)
Princess Mary of Teck (1867-1953)
George VI (1895-1952)
Queen Elizabeth II (b. 1926)
So, what does this mean? Well, not much. If we were to look at the total number of ancestors of Queen Elizabeth living 500 years ago -- taking into account all the cousin marriages that are common within royal families -- that number would still be at least one thousand. So Vlad Dracul is just one of a thousand other ancestors. So although we could say that the Queen has a little bit of Dracula blood in her, that bit is less than .1%.
If we look at it the other way, it is likely that Vlad Dracul has millions of descendants alive today and Queen Elizabeth would only be one of those millions of people. Remember: Being a descendant is not the same thing as being an heir. An heir is the most senior descendent and out of Vlad’s millions of descendants, the Queen would likely be way down the list in terms of the Dracula line of succession.