The national flag of Denmark is more commonly known as the Dannebrog. The name means "Danish cloth". The Dannebrog is red with a white cross that extends to the edges of the flag; the vertical part of the cross is shifted to the hoist side. The cross design of the Danish flag was subsequently adopted by the other Nordic countries; Sweden, Norway, Finland and Iceland.
According to ancient tradition, the flag was not made by humans but fell from the Heavens during the battle of Reval (modern day Tallinn in Estonia), in 1219. The flag of Latvia, even though not depicting a cross, also trace its origins to the colors from the battle of Reval.
Historians have a less colourful explanation for the origins of the flag. It is likely derived from old crusader banners of the time.
The old coat of arms of Lübeck was red with a white cross. The first Danish king known by a white crossed flag was also king of Lübeck.
The cross on the Dannebrog is similar to the cross of St Philip.