Why did German nationalists want Schleswig linked with Holstein?

German nationalists sought to keep Schleswig linked with Holstein primarily because of the long-standing political and historical bonds between the two duchies. Following the Napoleonic Wars, which spurred a rise in German national sentiment, these existing ties suggested to nationalists that the regions should form a single, unified state within the German Confederation.12

By maintaining this association, German nationalists aimed to detach Schleswig from Denmark, countering Danish efforts to incorporate Schleswig into the Danish state and establish the Eider River as the definitive border between Germany and Denmark. This desire for a unified Schleswig-Holstein was a central driver of the 1848 uprising and the subsequent tensions that led to the German-Danish War in 1864.12