The national flag of Denmark, Dannebrog, is red with a white Scandinavian 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, Iceland and the Faroe Islands, as well as the non-Nordic Scottish regions of Shetland and Orkney. During the Danish-Norwegian personal union, Dannebrog ("Danish cloth") was also the flag of Norway and continued to be, with slight modifications, until Norway adopted its current flag in 1821. Dannebrog is the oldest state flag in the world still in use by an independent nation. Prior to the use of Dannebrog, The legend states the origin of the flag to the Battle of Lyndanisse, also known as the Battle of Valdemar near Lyndanisse (Tallinn) in Estonia, on June 15, 1219. The battle was going badly, and defeat seemed imminent. But then, right when the Danes were about to give up, the flag fell from heaven. Grasping the flag before it could ever touch the ground, the king took it in his hand, and proudly waved it in front of his discouraged troops, giving them hope, and leading them to victory. The myth is clear.
The earliest source that indisputably links the red flag with a white cross to a Danish King, and to the realm itself, is found in a Dutch armorial, the "Gelre Armorial" (Dutch: Wapenboek Gelre, written between 1340 and 1370 (some sources say 1378 or 1386). Most historians claim that the book was written by Geldre Claes Heinen. The book displays some 1,700 coats-of-arms from all over Europe, in colour. It is now located at the Royal Library of Brussels.