Mariana of Austria (Maria Anna; 24 December 1634 – 16 May 1696) was Queen consort of Spain as the second spouse of King Philip IV, who was also her maternal uncle. At the death of her husband in 1665, Queen Mariana became regent for her son Charles II, the last Spanish Habsburg, and she remained an influential figure during his reign.

Queen Mariana is also known as a benefactress for funding in the mid-17th century the Jesuit voyage of Blessed Father Diego Luis de San Vitores and Saint Pedro Calungsod to Guam, in order to Catholicize the indigenous Chamorro people of her namesake Mariana Islands.

Born as Maria Anna on 24 December 1634 in Wiener Neustadt, Austria, she was the granddaughter of Holy Roman Emperor Ferdinand II. Her parents were Ferdinand III and Maria Anna of Spain, the sister of Maria Anna's future husband, King Philip IV of Spain. Her father, who would become emperor in 1637, was as yet only King of Hungary and Bohemia, and was away for most of his wife's pregnancy campaigning in the Thirty Years' War. Her grandfather Emperor Ferdinand II died when she was 3 and her father became Holy Roman Emperor Ferdinand III.

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