In the early 20th century the sanction of the king of Denmark was sought for a local Icelandic flag. Royal approval was available on the condition that the flag be different from any existing flag and always flown subordinate to the national flag of Denmark. To the blue flag with a white Scandinavian Cross proposed by political parties in Iceland, a red cross was added so that the colours of Denmark would be incorporated. Approval was given by the king on June 19, 1915. At sea the new flag could be used only in territorial waters, and on land it could be displayed on public buildings only together with the Danish flag. Icelanders continued to push for wider usage, and, finally, on December 1, 1918, full recognition was given to the flag at the same time that Iceland was constituted a separate kingdom under the Danish king. When Iceland became a republic on June 17, 1944, the flag was altered by a change to a darker shade of blue.
Blue and white had originally been chosen for several reasons. The first local flag of those colours, used only briefly, dated from 1809. In 1903 a coat of arms was granted to the island, showing a white or silver falcon on a blue shield. Blue and white were also the traditional colours of clothing worn by people in Iceland. Because most people felt that it was desirable to have a reflection of Scandinavian solidarity as well as national self-identity reflected in the flag, the Scandinavian Cross was central to the design. (See also the flag histories of Finland, Norway, and Sweden.)