In 1940, Denmark was invaded by the Nazis. King Christian X reluctantly cautioned his fellow Danes to accept the occupation, but there was widespread resistance. Denmark was the only occupied country in World War II to save all its Jews from extermination by smuggling them out of the country.
Beginning in 1944, Denmark's relationship with its territories changed substantially. In that year, Iceland declared its independence from Denmark, ending a union that had existed since 1380. In 1948, the Faroe Islands, which had also belonged to Denmark since 1380, were granted home rule, and in 1953, Greenland officially became a territory of Denmark.