It was officially named the Swedish National Day by the parliament of Sweden in 1983, and became a public holiday in 2005.

[1] The day is celebrated in honor of the election of Gustav Vasa as King of Sweden in 1523 and of the adoption of the constitutions of 1809 and 1974.

The tradition of celebrating this date began in 1916 at the Stockholm Olympic Stadium, in honor of the election of King Gustav Vasa on 6 June 1523 (according to the Julian calendar), as this was considered the foundation of modern Sweden.

Some question the validity of this as a national holiday, as the event occurred so long ago that it does not have a strong a presence in the social consciousness as, for example, the Norwegian Constitution Day, Syttende mai.

[2] In 2005, it became an official Swedish public holiday, replacing Whit Monday.