Warren said:Prince Andrew of Greece was the son of Prince William of Denmark (who became King George I of Greece).
William's sister (and Andrew's aunt) Princess Alexandra married Edward (Prince of Wales, later Edward VII), eldest son of Queen Victoria.
Edward's sister, Princess Alice, married Ludwig IV, the Grand Duke of Hesse and by Rhine [Hesse-Darmstadt]. Among their children was Princess Victoria.
Princess Victoria married Prince Louis of Battenberg (from another branch of the House of Hesse); they had two daughters, Alice and Louise.
Princess Louise married King Gustaf VI Adolf of Sweden, and Princess Alice married Prince Andrew of Greece.
So, after all that, Princess Victoria of Hesse-Darmstadt was the mother-in-law of Prince Andrew of Greece, and related (distantly) as well.
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Thanx so much- so, P. Andrew of Greece, P Philip's father, was related to K. Costantine's father, I just don't know if he was a nephew or what- maybe a brother ? I knew of course of Q Alexandra's brother, who became King of Greece. I find it so confusing.....