https://en.wikipedia.org/wiki/Duke_Anthony_Ulrich_of_Brunswick was from House of Welf as mentioned earlier and it says "Anthony Ulrich was the second son of Ferdinand Albert II, Duke of Brunswick-Lüneburg and Princess Antoinette of Brunswick-Wolfenbüttel. His mother's sister, Elizabeth, wife of Charles VI, Holy Roman Emperor, arranged for his marriage to HSH Duchess Elisabeth of Mecklenburg-Schwerin (known as "Anna Leopoldovna"), daughter of Charles Leopold, Duke of Mecklenburg-Schwerin, and granddaughter of Tsar Ivan V; and he was taken to Russia in 1733, so that he and Anna could get to know each other. The marriage took place in 1739. This marriage was intended to strengthen the relationships between the houses of Romanov and Habsburg." remember earlier the Habsburg's in EU?

HOW MUCH MORE EVIDENCE HAVE TO BE OUT THERE?

https://en.wikipedia.org/wiki/Duke_of_Holstein-Gottorp
https://en.wikipedia.org/wiki/List_of_consorts_of_Holstein-Gottorp
https://en.wikipedia.org/wiki/House_of_Bernadotte (Sweden royals)
"Its founder Charles XIV John of Sweden, born a Frenchman as Jean Bernadotte, was adopted by the elderly King Charles XIII of Sweden, who had no other heir and whose Holstein-Gottorp branch of the House of Oldenburg thus was soon to be extinct."

https://en.wikipedia.org/wiki/Princess_Victoria_Adelaide_of_Schleswig-Holstein is Sweden king Carl XVI Gustaf's maternal grandmother she belonged to the house of https://en.wikipedia.org/wiki/House_of_Gl%C3%BCcksburg "The House of Glücksburg (also spelled Glücksborg), shortened from House of Schleswig-Holstein-Sonderburg-Glücksburg, is a Dano-German branch of the House of Oldenburg, members of which have reigned at various times in Denmark, Norway, Greece and several northern German states.

Queen Margrethe II of Denmark, King Harald V of Norway, former king of Greece Constantine II, former Queen Anne-Marie of Greece, Queen Sofía of Spain and Prince Philip, Duke of Edinburgh (and his eldest son and heir to the British throne Charles, Prince of Wales) are patrilineal members of cadet branches of the Glücksburg dynasty" THESE ARE MAIN BLOODLINES CONNECTED TOGETHER HOLSTEIN-GOTTORP LINE IS ALSO ONE OF THE MAIN LINES.
https://en.wikipedia.org/wiki/George_II_of_Greece is connected to here and from these lines we get back to the Kantakouzenos/Cantacuzenus/Cantacuzene and Vlad the Impaler, also known Vovoids of Wallachia https://en.wikipedia.org/wiki/List_of_rulers_of_Wallachia