John Lackland, King of England is Prince William, Duke of Cambridge's 20th great grandfather!

Queen Elizabeth II
his mother

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George VI of the United Kingdom
her father

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Mary of Teck, Queen consort of the United Kingdom
his mother

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Princess Mary Adelaide of Cambridge, Duchess of Teck
her mother

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Prince Adolphus, Duke of Cambridge
her father

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Charlotte, Queen consort of the United Kingdom
his mother

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Karl I, Großherzog zu Mecklenburg-Strelitz
her father

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Adolph Friedrich II, Herzog zu Mecklenburg-Strelitz
his father

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Adolf Frederick I, Herzog von Mecklenburg-Schwerin
his father

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Sophie von Schleswig-Holstein-Gottorp, Herzogin zu Mecklenburg-Schwerin
his mother

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Adolf, Herzog von Holstein-Gottorp
her father

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Frederick I King of Denmark and Norway
his father

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Dorothea of Brandenburg
his mother

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John II "the Alchemist" Markgrave of Brandenburg-Kulmbach
her father

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Friedrich I Kurfürst von Brandenburg
his father

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Elisabeth von Meissen
his mother

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Friedrich II 'the Serious' Landgraf von Thüringen und Markgraf von Meißen
her father

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Friedrich I, Markgrave of Meissen
his father

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Margherita di Sicilia
his mother

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