Frederick IX of Denmark

Frederik IX of Denmark (Frederick Schleswig-Holstein-Sonderburg-Glucksburg, March 11, 1899 – January 14, 1972) was King of Denmark from 1947 until 1972.

Frederick was educated at the Danish Naval Academy (breaking Danish royal tradition by choosing a naval instead of an army career) and the University of Copenhagen.

He married Princess Ingrid of Sweden on May 24, 1935. They had three daughters,

• Princess Margrethe, later Margrethe II of Denmark.
• Princess Benedikte. Married Prince Richard zu Sayn-Wittgenstein-Berleburg in 1968.
• Princess Anne-Marie. Married Constantine II of Greece in 1964.

When he had no sons, in accordance with Denmark's Salic law, it was expected that his brother would inherit the throne. However, in 1953, an Act of Succession was passed, changing the method of succession from Salic law to cognatic primogeniture, meaning that his eldest daughter, Margrethe, could succeed if he had no sons. The King never did have any sons, so Princess Margrethe did succeed, as Margrethe II.