The Schleswig-Holstein Question

The duchies of Schleswig and Holstein, on the border between Denmark and Germany, show how nationalism turned old dynastic arrangements into bitter conflicts. Both duchies were ruled by the Danish king, but Holstein was mainly German-speaking and belonged to the German Confederation, while Schleswig had a mixed Danish and German population. Danish nationalists wanted to bind Schleswig more closely to Denmark, while German nationalists wanted both duchies to join Germany.

In 1848 German-minded rebels rose against Denmark, starting the First Schleswig War (1848–51), which ended with the old arrangement restored under great-power pressure. When Denmark tried again to integrate Schleswig in 1863, Prussia and Austria went to war in 1864 and took the duchies. The dispute was so complex that Lord Palmerston reportedly joked that only three people had ever understood it. A plebiscite in 1920 finally divided Schleswig along national lines, a rare peaceful solution.