
The Swedish flag's age is not really sure. The oldest known document in which it has a yellow cross on the blue bottom, is a letter of arms from Gustav Vasa to his son, Duke Johan in 1557.
However, there is an old saying that the Swedish flag was added when Erik the Holy saw the yellow cross on the blue sky as he landed in Finland during the first Swedish Crusade in 1157. He saw this as a sign from God and made it his banner. The problem with that legend is partly that there is no contemporary evidence of this crusade, partly that there are no pictures or descriptions of the blue-yellow banner until the mid-16th century, that is, 400 years later.
The blue-yellow colors, on the other hand, had been used for a long time as Swedish colors, among other things in the folk tongue weapons which became Magnus Ladulås king's weapon 1275, and in three crown weapons. The blue color was in the past considerably darker and the yellow sometimes went orange. In connection with the 300th anniversary of Gustav II Adolf's birth in 1894, a flag was introduced with lighter blue and yellow colors. This change was made because the former colors of the popular world were considered too gloomy and depressing.
Our current flag team was adopted in 1982, and it is said to include "that the color of the flag is light blue in the fields and gold on the cross". In more modern terms, the colors are referred to as blue PMS 301 and yellow PMS 116.