Iceland was settled in the late 9th and early 10th centuries, principally by people of Norse origin. In 930 A.D., the ruling chiefs accomplished a republican constitution and an assembly called the Althingi--the oldest parliament in the world. Iceland remained independent until 1262, when it entered into a treaty establishing a union with the Norwegian monarchy. Iceland passed to Denmark in the late 14th century when Norway and Denmark were united under the Danish crown.

In October 1946, the Icelandic and U.S. Governments agreed to terminate U.S. responsibility for the defense of Iceland, but the United States retained certain rights at Keflavik. Iceland became a charter member of the North Atlantic Treaty Organization (NATO) in 1949. After the outbreak of hostilities in Korea in 1950, and pursuant to the request of NATO military authorities, the United States and Iceland agreed that the United States should again be responsible for Iceland's defense. A bilateral defense agreement signed on May 5, 1951, is the authority for U.S. military presence in Iceland. Iceland is the only NATO nation with no standing military of its own.