The area of Iceland had been under the control of Denmark since 1380, although it formally remained in possession of Norway until 1814.
On 1 December 1918, the Act of Union recognised Iceland as a sovereign state, and it was now considered to be in personal union with Denmark. The Kingdom of Iceland received its own flag and coat of arms. The first and only King of Iceland was King Christian X of Denmark, and thus the first and only Queen of Iceland was his wife, Alexandrine of Mecklenburg-Schwerin.
In April 1940, Denmark was occupied by Germany, and as a result, the Icelandic parliament passed two resolutions, investing the Icelandic cabinet with the powers of the head of state, and it declared that Iceland would accept responsibility for foreign policy and coastal surveillance. In May 1941, a law was adopted to appoint a regent in order to represent the monarchy. The regency was entrusted to Sveinn Björnsson. Iceland remained neutral during the Second World War, but British military forces invaded and occupied Iceland until 1941.
Following a referendum held in May 1944, Iceland became a republic on 17 June 1944. Its former King sent a message of congratulations to the Icelandic people. King Christian X remained as King of Denmark and his descendants still sit on the Danish throne.