July 1920: Denmark Regains Some Lost Territory

Historically Contested Schleswig-Holstein

The Schleswig-Holstein question, was a 19th century controversy among Denmark, Prussia, and Austria over the status of Schleswig and Holstein. At this time the population of Schleswig was Danish in its northern portion, German in the south, and mixed in the northern towns and center. The population of Holstein was almost entirely German. After much contentious diplomacy, a rebellion—inspired by the Paris revolution of February 1848—led to an intervention in support of the rebels by Prussia. International opposition, however, forced the Prussians to withdraw and the Danes viewed the outcome as a victory. Matters festered, however. A succession crisis of 1863 gave the new German chancellor Otto von Bismarck a fresh opportunity to intervene and annex the duchies.

In the ensuing German-Danish War (1864), Danish military resistance was crushed by Prussia and Austria in two brief campaigns. By the Peace of Vienna (October 1864), Christian IX ceded Schleswig and Holstein to Austria and Prussia. In 1866, after Prussia had beaten Austria in the Seven Weeks War, both Schleswig and Holstein became part of Prussia.

Pro-German 1920 German Plebiscite Poster

Following Germany’s defeat in World War I, separate plebiscites were held in 1920 in the northern and southern portions of North Schleswig so that their respective inhabitants could choose between Denmark and Germany. The northern part of North Schleswig voted 70 percent to join Denmark, while the southern part voted 80 percent to remain within Germany. The northern part of North Schleswig thus became part of Denmark as the Danish province of Slesvig, effective with King Christian X's ratification of the treaty with Germany on 6 July 1920. The resulting Danish-German boundary in Schleswig has lasted to the present day with a minor adjustment following the Second World War and is no longer a matter of contention.

Present-day Border (Compare to Historic Map Above)

Sources: Encyclopedia Britannica Article; Wikipedia