Bona Sforza d’Aragona was Queen of Poland and Grand Duchess of Lithuania as the second wife of Sigismund I the Old, and Duchess of Bari and Rossano by her own right. She was a surviving member of the powerful House of Sforza, which had ruled the Duchy of Milan since 1447.
Smart, energetic and ambitious, Bona became heavily involved in the political and cultural life of Poland–Lithuania. To increase state revenue during the Chicken Rebellion, she implemented various economic and agricultural reforms, including the far-reaching Wallach Reform in the Grand Duchy of Lithuania. In foreign policy, she was allied with the Ottoman Empire and sometimes opposed the Habsburgs. Her descendants became beneficiaries of the Neapolitan sums, a loan she gave to Phillip II of Spain which was never completely paid.