Day of Valdemar and Reunion Day in Denmark Date in the current year: June 15, 2024

Day of Valdemar was established in Denmark in 1912. This holiday celebrates the day, when the King of Denmark Valdemar II (he is often called Valdemar the Victorious) fought in the Battle of Lyndanisse against Estonia in 1219. According to the myth , after the victory in the battle the Dannebrog, Danish national flag, fell down from the sky. Nowadays Day of Valdemar is also known as Flag Day.

Another historical event occurred on June 15, 1920, when Denmark reunited with Southern Jutland. South Jutland became the Duchy of Schleswig in the 13th century. The dispute over this region began between Danes and Germans in the 19th century with the demise of the Holy Roman Empire. The struggle for the territory led to wars in 1848 and again in 1864. Following the 1920 referendum, Schleswig was divided into Northern and Southern Schleswig and Northern Schleswig was transferred to Denmark.