Denmark has the oldest continuously used national flag: the red-and-white Dannebrog. Its distinctive white Nordic cross reaches the edges of the red field, a design later echoed by several other Scandinavian flags.
Danish tradition says the flag fell from the sky during the Battle of Valdemar II at Lindanise in Estonia in 1219. Historians treat that story as a legend, while documentary evidence places the flag’s use much later, including medieval illustrations and records from the 14th century. The design became especially important as Denmark’s national symbol and was formally standardized for different uses over time.
A common mix-up is confusing “oldest flag” with “oldest continuously used national flag.” Several flags have ancient origins, but Denmark’s claim concerns uninterrupted use as a national flag. Norway, Sweden, and the United Kingdom also have historically old designs, yet their current flags were adopted later or changed substantially.