The Duke of Holstein was a noble title associated with the region of Holstein, located in present-day northern Germany. This title was held by various members of the House of Oldenburg, which played a significant role in the history of Denmark and northern Germany. The dukedom was often contested and influenced by the political dynamics of surrounding territories. Throughout history, the Duke of Holstein had varying degrees of power and autonomy, especially during the Middle Ages. The title was linked to the governance of the region and its people, impacting local politics and alliances. The dukedom eventually became part of larger political entities, including the Duchy of Schleswig-Holstein.