The Duke of Swabia was a title held by the rulers of the region of Swabia in present-day southwestern Germany during the Middle Ages. This title was significant in the Holy Roman Empire, where the dukes played a crucial role in local governance and military leadership. The most notable Duke of Swabia was Frederick II, who later became the Holy Roman Emperor. The duchy was established in the 10th century and was part of the larger political landscape of the empire. The dukes often engaged in power struggles with other noble families and the emperor, influencing the region's political dynamics. The title eventually became less prominent as the political structure of the Holy Roman Empire evolved.