The white cross represents Christianity, and the red field is associated with battle. The design influenced all other Nordic flags.
History
The 'Dannebrog' is the oldest continuously used national flag in the world. Legend says it fell from the sky during the Battle of Lyndanisse (Estonia) in 1219, giving victory to the Danes.
Construction
A 1:2 ratio. A red field with a white Nordic cross extending to the hoist side.