Schleswig-Holstein is the northernmost of the sixteen states of Germany, comprising most of the historical duchy of Holstein and the southern part of the former Duchy of Schleswig. Its capital city is Kiel; other notable cities are Lübeck, Flensburg and Neumünster.
The former English name was Sleswick-Holsatia, the Danish name is Slesvig-Holsten, the Low German name is Sleswig-Holsteen, and the North Frisian name is Slaswik-Holstiinj. Historically, the name can also refer to a larger region, containing both present-day Schleswig-Holstein and the former South Jutland County (Northern Schleswig) in Denmark.
The term Schleswig takes its name from the city of Schleswig. The name derives from the Schlei inlet in the east and vik meaning inlet or settlement in Old Saxon and Old Norse. The name is similar to the place-names ending in the "-wick" or "-wich" element along the coast in the United Kingdom.
The Duchy of Schleswig or Southern Jutland was originally an integral part of Denmark, but was in medieval times established as a fief under the Kingdom of Denmark, with the same relation to the Danish Crown as for example Brandenburg or Bavaria vis-à-vis the Holy Roman Emperor. Around 1100 the Duke of Saxony gave Holstein, as it was his own country, to Count Adolf I of Schauenburg.
Schleswig and Holstein have at different times belonged in part or completely to either Denmark or Germany, or have been virtually independent of both nations. The exception is that Schleswig had never been part of Germany until the Second War of Schleswig in 1864. For many centuries, the King of Denmark was both a Danish Duke of Schleswig and a German Duke of Holstein, the Duke of Saxony. Essentially, Schleswig was either integrated into Denmark or was a Danish fief, and Holstein was a German fief and once a sovereign state long ago. Both were for several centuries ruled by the kings of Denmark. In 1721 all of Schleswig was united as a single duchy under the king of Denmark, and the great powers of Europe confirmed in an international treaty that all future kings of Denmark should automatically become dukes of Schleswig, and consequently Schleswig would always follow the same line of succession as the one chosen in the Kingdom of Denmark.
The German national awakening following the Napoleonic Wars led to a strong popular movement in Holstein and Southern Schleswig for unification with a new Prussian-dominated Germany. However, this development was paralleled by an equally strong Danish national awakening in Denmark and northern Schleswig. It called for the complete reintegration of Schleswig into the Kingdom of Denmark and demanded an end to discrimination against Danes in Schleswig. The ensuing conflict is sometimes called the Schleswig-Holstein Question. In 1848 King Frederick VII of Denmark declared that he would grant Denmark a liberal constitution and the immediate goal for the Danish national movement was to ensure that this constitution would not only give rights to all Danes, i.e., not only in the Kingdom of Denmark, but also to Danes (and Germans) living in Schleswig. Furthermore, they demanded protection for the Danish language in Schleswig since the dominant language in almost a quarter of Schleswig had changed from Danish to German since the beginning of the 19th century.
A liberal constitution for Holstein was not seriously considered in Copenhagen, since it was a well-known fact that the political élite of Holstein had been far more conservative than Copenhagen's. This proved to be true, as the politicians of Holstein demanded that the Constitution of Denmark be scrapped — not only in Schleswig but also in Denmark. They also demanded that Schleswig immediately follow Holstein and become a member of the German Confederation, and eventually a part of the new united Germany. These demands were rejected and in 1848 the Germans of Holstein and Southern Schleswig rebelled. This was the beginning of the First War of Schleswig (1848–51) which ended in a Danish victory at Idstedt.
In 1863 conflict broke out again as King Frederick VII of Denmark died leaving no heir. According to the line of succession of Denmark and Schleswig, the crowns of both Denmark and Schleswig would now pass to Duke Christian of Glücksburg (the future King Christian IX); the crown of Holstein was considered to be more problematic. This decision was challenged by a rival pro-German branch of the Danish royal family, the House of Augustenborg who demanded, as in 1848, the crowns of both Schleswig and Holstein. The passing of a common constitution for Denmark and Schleswig in November 1863 then gave Otto von Bismarck a chance to intervene and Prussia and Austria declared war on Denmark. This was the Second War of Schleswig which ended in a Danish defeat. British attempts to mediate failed, and Denmark lost Schleswig (Northern and Southern Schleswig), Holstein, and Lauenburg to Prussia and Austria.
Following the Austro-Prussian War of 1866, section five of the Peace of Prague stated that the people in northern Schleswig should be granted the right to a referendum on whether they would remain under Prussian rule or return to Danish rule. This promise was never fulfilled by Prussia.
Following the defeat of Germany in World War I, the Allied powers arranged a plebiscite in northern and central Schleswig. In northern Schleswig (10 February 1920) 75% voted for reunification with Denmark and 25% voted for Germany. In central Schleswig (14 March 1920) the results were reversed; 80% voted for Germany and just 20% for Denmark, primarily in Flensburg. No vote ever took place in the southern third of Schleswig, although it was planned. For the referendum under authority of an international commission (CIS, Commission Internationale de Surveillance du Plébiscite au Slesvig) two (primarily three) election-zones were created. Primarily three zones were planned, Zone III should involve the rest of Southern Schleswig. Denmark passed on an election in this zone. Just the votes for the whole zone were crucial, not the dissenting votes in a single Kreis (district) or city:
On 15 June 1920, northern Schleswig officially returned to Danish rule. The Danish/German border was the only one of the borders imposed on Germany by the Treaty of Versailles after World War I which was never challenged by Adolf Hitler.
In 1937 the Nazis passed the so-called Greater Hamburg Act (Groß-Hamburg-Gesetz), where the nearby Free and Hanseatic City of Hamburg was expanded, to encompass towns that had formally belonged to the Prussian province of Schleswig-Holstein. To compensate Prussia for these losses (and partly because Hitler had a personal dislike for Lübeck), the 711-year-long independence of the Hansestadt Lübeck came to an end, and almost all its territory was incorporated into Schleswig-Holstein.
After the Second World War, the Prussian province Schleswig-Holstein came under British occupation. On 23 August 1946, the Military Government abolished the province and reconstituted it as a separate Land.
Because of the Expulsion of Germans after World War II the population of Schleswig-Holstein increased 33 percent (860,000 people).