The Duke of Ferrara was a title held by the rulers of the Duchy of Ferrara, a small but influential state in northern Italy. The duchy was established in the 15th century and became known for its cultural and artistic contributions during the Renaissance. The ruling family, the Este, played a significant role in promoting the arts and attracting notable artists and scholars to the region. The most famous Duke of Ferrara was Alfonso I d'Este, who ruled from 1505 to 1534. He was known for his patronage of the arts and his marriage to the renowned poet Lucrezia Borgia. The duchy was eventually absorbed into the Papal States in the 17th century, marking the end of its independent rule.