Iceland

The Danish–Icelandic Act of Union, an agreement with Denmark signed on 1 December 1918 and valid for 25 years, recognised Iceland as a fully sovereign state in a personal union with Denmark. The Government of Iceland established an embassy in Copenhagen and requested that Denmark handle Icelandic foreign policy. Danish embassies around the world displayed two coats of arms and two flags: those of the Kingdom of Denmark and those of the Kingdom of Iceland.
During World War II, Iceland joined Denmark in asserting neutrality. After the German occupation of Denmark on 9 April 1940, the Althing replaced the King with a regent and declared that the Icelandic government should assume the control of foreign affairs and other matters previously handled by Denmark. A month later, British armed forces invaded and occupied the country, violating Icelandic neutrality. In 1941, the occupation was taken over by the United States so that Britain could use its troops elsewhere, an arrangement reluctantly agreed to by the Icelandic authorities.
• Independent republic 1944–present
On 31 December 1943, the Danish–Icelandic Act of Union expired after 25 years. Beginning on 20 May 1944, Icelanders voted in a four-day plebiscite on whether to terminate the personal union with Denmark, abolish the monarchy, and establish a republic. The vote was 97% to end the union, and 95% in favour of the new republican constitution. Iceland formally became a republic on 17 June 1944, with Sveinn Björnsson as its first president.