Denmark uses the Dannebrog, the red flag with a white Nordic cross that is widely regarded as the world’s oldest continuously used national flag.
The Danish flag’s famous origin story says it fell from the sky during the Battle of Lindanise in 1219, helping Danish forces win in present-day Tallinn, Estonia. Historians treat that story as a later legend rather than contemporary evidence. The design is securely documented in medieval sources, including the Gelre Armorial from roughly 1340–1370.
The cross reflects the flag’s Christian and medieval European background, while its offset shape became a model for the Nordic-cross flags of countries such as Sweden, Norway, Finland and Iceland. The Dannebrog was used mainly as a royal or military emblem before becoming broadly accepted as a national flag.
Another common misconception is that private citizens could always fly it freely. Denmark restricted private use in 1834, then permitted it again in 1854. The modern flag was formally recognized as a national flag in 1625.