Why was Holstein more closely connected to Germany than Schleswig was?

Holstein was more closely connected to Germany than Schleswig primarily due to its political status and demographic composition. While both regions were ruled as duchies by the kings of Denmark, Holstein held a unique dual status: it was a fief of the Holy Roman Empire and, following 1815, became a member of the German Confederation.12

In contrast, Schleswig was historically a dependency of Denmark. Furthermore, the population of Holstein was almost entirely German, whereas Schleswig’s population was ethnically mixed, with a Danish-speaking majority in the north and a German-speaking majority in the south. These factors fueled 19th-century nationalist movements that sought to align Holstein—and by extension, the German-majority areas of Schleswig—more closely with the German states rather than Denmark.21