Carl XVI Gustaf (Carl Gustaf Folke Hubertus; born 30 April 1946) is the King of Sweden. Carl Gustaf was born during the reign of his paternal great-grandfather, King Gustaf V. He is the youngest child and only son of Prince Gustaf Adolf, Duke of Västerbotten, and Princess Sibylla of Saxe-Coburg and Gotha. His father died in January 1947 in an airplane crash in Denmark when Carl Gustaf was nine months old. Carl Gustaf became crown prince and heir apparent to the Swedish throne at the age of four when his grandfather Gustaf VI Adolf acceded to the throne in 1950.
https://en.wikipedia.org/wiki/Carl_XVI_Gustaf