The flag of Sweden is the national flag of the Kingdom of Sweden. It consists of a yellow or gold Nordic Cross (i.e. an asymmetrical horizontal cross, with the crossbar closer to the hoist than the fly, with the cross extending to the edge of the flag) on a field of blue. The Nordic Cross design traditionally represents Christianity. The design and colors of the Swedish flag are believed to have been inspired by the present coat of arms of Sweden of 1442, which is blue divided quarterly by a cross pattée of gold, and modeled on the Danish flag. Blue and yellow have been used as Swedish colours at least since King Magnus III’s royal coat of arms of 1275.
According to early modern legend, the 12th-century King Eric IX saw a golden cross in the sky as he landed in Finland during the First Swedish Crusade in 1157. Seeing this as a sign from God he adopted the golden cross against a blue background as his banner.
It has been suggested that the Swedish origin legend is chosen to counter a parallel origin story for the Danish flag, also recorded in the 16th century. According to this theory, the Swedish flag was created during the reign of King Charles VIII, who also introduced the coat of arms of Sweden in 1442. The national coat of arms is a combination of King Albert’s coat of arms of 1364 and King Magnus III’s coat of arms of 1275, and is blue divided quarterly by a golden cross pattée.
Other historians claim that the Swedish flag was blue with a white cross before 1420, and became blue with a golden cross only during the early reign King Gustav I, who deposed King Christian II in 1521.