Since 1983, Sweden has celebrated its National Day on 6th June. This is the date on which Gustav Vasa was crowned king in 1523 and on which a new constitution was adopted in 1809. The original idea came from Artur Hazelius, who founded the Skansen open-air museum in Stockholm and held a national day celebration there on 6th June as early as the 1890s. At the 1893 World Fair in Chicago, Sweden presented Midsummer Day as a form of Swedish national day, and it was subsequently proposed that this arrangement be officially sanctioned at home. As Hazelius organised Skansen’s national day festivity at the end of spring, Sweden celebrated the occasion twice a year in the 1890s. In 1916, Hazelius’s idea was officially adopted and 6 June became Swedish Flag Day. The name celebrated the fact that Sweden had acquired its own flag following the dissolution of the union with Norway in 1905.