The exact age of the Swedish Flag is not known, but the oldest recorded pictures of a blue cloth with a yellow cross date from the 16th century. As decreed in a royal warrant of 1569, the yellow cross was always to be borne on Swedish battle standards and banners, as the Swedish Coat of Arms was blue divided quarterly by a cross of gold. The design of the Swedish flag is probably taken from the Danish flag, and its blue and yellow colours possibly come from the Coat of Arms. Not until the 1620s–i.e., during the reign of Gustav II Adolf–do we find any reliable evidence of the blue flag with a yellow cross being worn by Swedish vessels. According to our oldest existing flag warrant, from 1663, a triple-tailed flag was to be used except by merchant ships, whose flag was square-cut. Nowadays the use of the triple-tailed pennon is reserved for the Royal Family and the armed forces. The Royal Family may also charge its flags either with the Lesser or the Greater Coat of Arms in the centre of the cross.
Since 1916, 6 June has been celebrated as the Swedish Flag Day. This finally also became Sweden’s National Day in 1983. The reasons for the choice of date are twofold: the election of Gustav Vasa as Sweden’s king on 6 June 1523 laid the foundation of Sweden as a separate state; and on the same date in 1809, Sweden adopted a new constitution which included the establishment of civil rights and liberties.
The colours and design of the flag are laid down in the Flag Act of 1982.
The flag is normally hoisted at 08:00 hrs from 1 March to 1 October, otherwise at 09:00 hrs. It is lowered at sunset, but no later than 21:00 hrs. There are some 15 official flag days, including the special celebrations of the Royal Family, May Day, Election Day, United Nations Day (24 October) and Nobel Day (10 December). The flag may also be flown on special local or private family occasions.