The flag of Denmark, the current design of a white Scandinavian cross on a red background was officially adopted in 1307 or earlier. The Flag of Denmark also holds the Guinness World Record for the oldest continuously used national flag.
According to legend, the flag came into Danish possession during the Battle of Lyndanisse in 1219. The Danes were on a failing crusade in Estonia, but after praying to God, a flag fell from the sky. After this event, Danish King Valdemar II went on to defeat the Estonians. The first recorded use of the flag appeared less than 100 years later. This legend has no historical or factual record, though many hold it to be true.