ern 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 Gl�cksburg (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 Pl�biscite au Slesvig) two (primarily three) election-zones were created. Primarily
