He succeeded his father in 1505 and became the 3rd Duke of Ferrara. By this time his first wife, Anna Sforza, had been dead since 1497 and he had married Lucrezia Borgia in 1502. However, soon the peace of Ferrara was destroyed when two of his younger brothers, Giulio and Cardinal Ippolito d'Este, both fell in love with the same girl. However, the girl preferred Giulio who then was badly beaten up by the men of his brother Ippolito. Giulio was left bleeding and half blind. Alfonso persuaded Giulio not to take revenge but Giulio, with Ferrante, another of the Este brothers, plotted to murder both Alfonso the Duke and Ippolito the Cardinal. However, Alfonso got to hear about the conspiracy and Giulio and Ferrante were brought to trial together with their fellow conspirators. The latter were cruelly executed, the two brothers were imprisoned, Ferrante died in prison thirty years later, and Giulio was pardoned only when he was eighty-one years old.

His marriage to Lucrezia Borgia was a happy one and seven children were born. Their first child had been a stillborn daughter; Ercole survived to become the next Duke of Ferrara; Ippolito became a Cardinal; Alexander died aged two; Eleonore who became a nun; Francesco, became Prince of Massa, married and fathered two daughters; then another stillborn daughter.

In Ferrara, Lucrezia had gained the reputation of a charming, graceful and happy Duchess. She had befriended Alfonso's sister, Isabella d'Este, Duchess of Mantua. After seventeen happy years she died, sincerely mourned by her husband Alfonso.

For the protection of Ferrara he fortified the city and added cannons to the city's defence. He enjoyed the making of cannons and was found regularly in the forge. He had tried to keep the peace with Pope Julius II but this Pope wanted to destroy the power of the Este family. At the age of sixty-six the Pope took to the field in full armour and led the papal forces into battle against Alfonso in 1511. During the battle which ensued at Mirandola, the Pope was almost kidnapped by an Este Lieutenant. However, the Pope took Mirandola but failed to defeat the Este family.

In the last twenty years of his life he maintained his power by making political alliances with King Charles VIII of France and also with the Emperor Charles V. He was able to buy back the territories of Modena and Reggio. In these years he also fathered two more sons by Laura Dianti and may have married her. He died aged only fifty-eight.

Source: Leo van de Pas