Margaret of Austria (25 December 1584 – 3 October 1611) was Queen consort of Spain and Portugal by her marriage to King Philip III and II. Margaret was the daughter of Archduke Charles II of Austria and Maria Anna of Bavaria and thus the paternal granddaughter of the Holy Roman Emperor Ferdinand I. Her elder brother was the Archduke Ferdinand, who succeeded as Emperor in 1619. Two of her sisters, Anna and Constance, through their subsequent marriages to King Sigismund III Vasa, became Queens of Poland. Margaret married Philip III of Spain, her first-cousin, once-removed, on 18 April 1599.

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