Today marks 70 years since the death of Prince Gustaf Adolf of Sweden, Duke of Västerbotten, who was second in line to the Swedish Throne at the time of his death in a plane crash in Denmark aged 40. The eldest son of then Prince Gustaf Adolf of Sweden (grandson of then King Oscar II of Sweden) and Princess Margaret of Connaught (a granddaughter of Queen Victoria), Gustaf Adolf was third-in-line to the Swedish throne, after his grandfather and father. Losing his mother quite young, Prince Gustaf Adolf was instrumental in welcoming Lady Louise Mountbatten (aunt of the Duke of Edinburgh and Lady Pamela Hicks) when she married his father in 1922. In 1932, he married Princess Sibylla of Saxe-Coburg-Gotha, with whom he had four daughters, the Haga Princesses, and a son, now King Carl XVI Gustaf of Sweden. At the time of his death, Prince Gustaf Adolf was second in line to the Swedish Throne, after his father. The was the nephew of Lady Patricia Ramsay, and elder brother of, among others, Queen Ingrid of Denmark and Prince Bertil of Sweden, Prince Gustaf Adolf was related to most of the crowned heads of Europe. Among his nieces were Queen Margrethe II of Denmark and Queen Anne Marie of Greece.