The Prussian military band is playing the Königgrätzer Marsch. The march was
composed in 1866 by Johann Gottfried Piefke in commemoration of the Battle of Königgrätz, the decisive battle of the Austro-Prussian War, in which the Kingdom of Prussia defeated the Austrian Empire. Thus, the march was composed two years after the conclusion of the Second War of Schleswig.
During the Battle of Dybbøl, Prince Friedrich Karl tells Bandmaster Piefke to play music for the Prussian soldiers digging the trenches toward Danish lines. The song played is the "Königgrätzer Marsch", one of the most famous German marches. This song would not be composed until after the Battle of Königgrätz, during the Austro-Prussian War, over two years after the Battle of Dybbøl.