The Duke of Schleswig-Holstein is a historical title associated with the regions of Schleswig and Holstein in northern Germany. This title was held by various noble families, most notably the House of Oldenburg and the House of Schleswig-Holstein-Sonderburg-Glücksburg. The dukedom played a significant role in the political landscape of Europe, particularly during the 19th century, when conflicts arose over the territories. The title became particularly prominent during the Schleswig Wars, which were fought between Denmark and the German Confederation in the mid-1800s. The outcome of these conflicts influenced the future of both Denmark and Germany, leading to changes in territorial control and national identity in the region.