The Duke of Modena was a title held by the rulers of the Duchy of Modena, a small state in northern Italy. This duchy was established in the 14th century and became part of the larger region of Emilia-Romagna. The dukes were part of the House of Este, a prominent noble family that played a significant role in Italian history. The last Duke of Modena was Francesco IV, who ruled until 1859 when the duchy was annexed to the Kingdom of Sardinia. This event was part of the broader unification of Italy, which led to the establishment of the modern Italian state. The legacy of the dukes can still be seen in the architecture and culture of Modena today.