The Duke of Hesse refers to a title held by the rulers of the historical region of Hesse in central Germany. The title emerged in the 13th century and was associated with various principalities, including Hesse-Kassel and Hesse-Darmstadt. The dukes played significant roles in the political landscape of the Holy Roman Empire and later in the formation of modern Germany. The last reigning duke was Ernst Ludwig, who ruled until the end of World War I in 1918. Following the war, the monarchy was abolished, and the title became largely ceremonial. Today, descendants of the ducal family still exist, maintaining cultural and historical ties to the region.