1219 during Valdemar Sejrs crusade to Estonia. The flag should have fallen down from the sky and thus have been giving the Danish troops new strength.
T
he Swedes seems to have copy this legend. According to the Swedes "Erik the Holy"
got the yellow cross on a blue sky during his crusades in Finland 1157.
There are many theories about the Swedish flag, one is that the Swedish flag should have been a resistance flag against the Danish union in the middle of the
Valdemar Atterdag's
(1320-1375) crest