Denmark’s flag is traditionally regarded as the oldest continuously used national flag, with its origin dated to 1219.
Known as the Dannebrog, it is a red field bearing a white Scandinavian cross. The cross design later influenced the flags of other Nordic countries, including Sweden, Norway, Finland and Iceland. Its vertical arm is shifted toward the hoist, a layout now associated with Nordic flags.
According to Danish tradition, the banner fell from the sky during the Battle of Lindanise, near present-day Tallinn in Estonia, on 15 June 1219, during the campaign of King Valdemar II. The story was recorded in sixteenth-century texts, so the miraculous origin is a legend rather than an independently proven eyewitness account.
That distinction explains why historians sometimes qualify the claim. The flag’s continuous national use is difficult to document for every year of the intervening centuries, but Denmark’s banner remains the standard trivia answer to the “oldest continuously used national flag” question. Its modern state use developed gradually from royal and military traditions.