About Princess Sibylla of Saxe-Coburg and Gotha
Princess Sibylla of Saxe-Coburg and Gotha (Sibylle Calma Marie Alice Bathildis Feodora; 18 January 1908 – 28 November 1972) was a member of the Swedish royal family and the mother of the current king of Sweden, Carl XVI Gustaf. Born into the House of Saxe-Coburg and Gotha, Sibylla was the daughter of Charles Edward, the last duke of Saxe-Coburg and Gotha. She became a Swedish princess when she married Prince Gustaf Adolf, Duke of Västerbotten in 1932. She thus had the prospect of one day becoming queen, but the prince was killed in an airplane crash in 1947 and did not live to ascend the Swedish throne. Her son became king the year after her death. In November 1931, Sibylla was in London to attend the wedding of her paternal first cousin Lady May Cambridge as a bridesmaid.
Biography source: Wikipedia. The profile adds birthday-specific historical context from the Celebs Birthday Today editorial database.