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Centennial of the Danish – Icelandic Union Act of 1918

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Tomorrow, November 30, 2018, marks the centennial of the signing of the Danish-Icelandic Forbundslov (Danish-Icelandic Union Act), which entered into force the following day on December 1, 1918.

Forbundslov 1918 no. 86 of Nov. 30. Photo by Elin Hofverberg.

Iceland—originally a Norwegian province—had been a part of Denmark ever since Norway became a part of Denmark in the 14th century under Queen Margaret I. It remained part of Denmark even after Norway gained its short-lived independence before becoming part of Sweden in 1814.

The road towards Icelandic independence began with the Constitution of 1874 (Forfatningslov for Islands særlige Anliggender) and the Home Rule Amendments of 1903, which took effect in 1904. A number of powers previously exercised by the Danish Realm were transferred to the Minister of Icelandic Affairs. The Minister, previously part of the cabinet in Copenhagen, was now seated in Reykjavik, had to be fluent in Icelandic, and—most importantly—could receive a vote of no confidence by the Althingi, the Icelandic Parliament.

Lov om ministers ansvarlighed [Act on Icelandic Minister’s Responsibilities]. (Mar. 4, 1904.) Photo by Elin Hofverberg.
1903 Amendment of 1874 Constitution. Photo by Elin Hofverberg.
















However, Icelanders, who saw Norway gain independence from Sweden in 1905, were still not satisfied and wanted recognition as a sovereign nation.

What Made the 1918 Union Act Special?

The 1918 Union Act stated that Iceland was a sovereign nation in a personal union with Denmark under one king, Christian X, who had assumed the throne just six years earlier. Subject to the Union Act, the succession rules could not be changed without Iceland’s consent nor could the king assume power over another country without Iceland’s consent. Iceland and Denmark remained in a monetary union and Denmark was still responsible for Iceland’s foreign affairs.

King Christian X of Denmark. (Bain News Service, publisher. 1915-1920). Library of Congress Prints and Photographs Division,

The Renewal Clause = Icelandic Independence!

The Union Act was to be renewed after 25 years, following a period of re-negotiation that was specified to take place between January 1, 1941 and December 31, 1943. (Union Act, §18 ). It stipulated that either state could terminate the union if they could not agree on a new union agreement during this period. In 1940, Nazi Germany occupied Denmark. Iceland therefore determined that the Danish king was no longer able to rule Iceland and decided to take control of its exports and foreign affairs. Following a May 1944 national referendum on terminating the Danish-Icelandic Union, Iceland declared independence on June 17, 1944 at Thingvellir.

On May 20-23, 1944, Icelanders voted overwhelmingly in favor of terminating the Danish-Icelandic Union and adopting a Republic. Results seen here as published in Stjórnartídini. Photo by Elin Hofverberg.

A formal Danish termination of the 1918 Union was issued on May 16, 1950 (Lov om ophævelse af Dansk-islandsk Forbundslov m.m. [Act on Termination of the Danish-Icelandic Union Act etc.]). The Act also provided for the treatment of Icelandic citizens residing in Denmark. Under the law, Icelandic citizens who had resided in Denmark between 1936 and 1946 were treated the same way as Danes, with the exception that Icelandic citizens did not need to perform mandatory military service in Denmark.

The Role the World Wars Had on Icelandic Independence

Icelandic independence arrived on the coattails of the First World War and the Second World War. The 1918 Union Act was signed less than three weeks after the WWI armistice. The proclamation of the Icelandic Republic—and the recognition by the United States—came in the middle of WWII.

Danish-Iceland Relationship

Even today, Iceland and Denmark share a special bond with legal standing that sets them apart from other Nordic nations. For example, the Compulsory School Act requires that Danish is taught as a second language, in addition to English, in Icelandic schools.

Centennial Celebrations

If you happen to be in Iceland, the Althingi—the Icelandic Parliament—will be open to the public on December 1.

For those of us who are not fortunate enough to be there for the celebrations, the Law Library has a number of interesting collection pieces in addition to the laws mentioned above.

You may also want to read more about the First Icelandic President Sveinn Björnsson or King Christian X, the last Icelandic King.

We hope you visit us soon!

Update: This was originally published as a guest post by Elin Hofverberg. The author information has been updated to reflect that Elin is now an In Custodia Legis blogger.


  1. I think it of some note in this discussion that Iceland was formally occupied by British, and subsequently by Canadian and U.S. forces during WWII. Only the U.S. military presence was agreed to by the Icelandic government, and, although no resistance was offered, they viewed the British/Canadian presence as a violation of their sovereignty. It was during this time that the referendum and declaration of independence took place. American Army and Navy personnel and Commonwealth forces eventually numbered as many as 30,000.
    I seek to make no point here, only a fleshing out of the historical background.

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