Bona Sforza (2 February 1494 or 2 February 1493 – 19 November 1557) was a member of the powerful Milanese House of Sforza. In 1518, she became the second wife of Sigismund I the Old, the King of Poland and Grand Duke of Lithuania, and became the Queen of Poland and Grand Duchess of Lithuania.

She was the third child of Gian Galeazzo Sforza and his wife Isabella of Naples. Her older brother was Francesco Sforza and her sisters were Ippolita Maria and Bianca Maria. All of Bona's siblings died young.

When her mother Isabella of Naples died in 1524, Bona succeeded to the titles Duchess of Bari and Princess of Rossano. She also became the holder of the Brienne claim to the title of King of Jerusalem.

Early years

Bona was born into the powerful and wealthy Italian Sforza dynasty who had ruled Milan since 1447. Although her father belonged to the authority of the Duchy of Milan, he was ousted by his uncle Ludovico Sforza, known to history as "Il Moro". He exercised power on behalf of the young prince, until his death in 1494 at the castle in Pavia. Shortly afterwards, the Princess Isabella, together with her daughters, went to Bari. To regain political significance and their former possessions, Isabella had to find a husband for Bona (her surviving daughter). Her first attempts were unsuccessful due to the unfavourable political situation at the time but due to the support of the House of Habsburg she succeeded in marrying Bona to the widowed Polish King Sigismund I the Old. The marriage ceremonies and Bona's coronation were held in Krakow on 18 April 1518.

In her youth, Bona obtained a good education. Her teacher was Crisostomo Colonna, a member of the Academy of Pont, who supervised her education along with Antonio Galateo. She received instruction in history, law, administration and theology. She was thrifty, economical, and she also had the ability to influence people. She demonstrated this skill in all her activities.

Queen of Poland

Almost from the beginning of her life in Poland, Queen Bona tried to gain a strong political position. She began to form her own cabal and also benefited from the support of the king. She was also supported by Piotr Kmita Sobieński, Andrew Ladislaus and Piotr Gamrat, taking them to her offices and creating the so-called Triumvirate. She managed to also get Pope Leo X to decide on the appointment of fifteen ecclesiastical benefice of very high importance (e.g. in Kraków, Gniezno, Poznań, Włoclawek and Frombork).

Bona came out of the belief that one of the most important things needed for the effective implementation of policies and plans for strengthening royal authority is access to appropriate high finance. Therefore she set herself the objective of magnification and the assembly domain of dynastic wealth as much as possible, which would give the Jagiello family financial independence. The family gained numerous estates in Lithuania, and finally in 1536-1546 they took over the Grand Duchy of Lithuania. This generated huge profits.

In 1527, as a result of a fall from a horse, the queen gave birth prematurely to her second son Albert, who died at birth. After this event, the Queen could not have any more children. Bona, wanting to ensure the continuity of the Jagiellonian dynasty on the Polish throne, decided to make the nobles and magnates to recognise her only son, the minor Sigismund Augustus as heir to the throne. First, the Lithuanian nobles gave him the ducal throne (ca. 1527-1528). Then, in 1529 he was crowned Sigismund II Augustus. This led to huge opposition from Polish lords, which led to the adoption of the bill that the next coronation would take place after the death of Sigismund Augustus, and that it would do so with the consent of all the noble brothers.

From the outset, Bona was wary of the growing power of the Radziwiłł family and was later accused of poisoning her daughter-in-law Barbara Radziwiłł.

In foreign policy, she was a fierce opponent of the Habsburgs and a supporter of a closer alliance with France. In Hungary during the wars that took place after the Battle of Mohacs in 1526, supported by János Szapolyai against the Habsburgs. Bona also sought to maintain good relations with Sublime Porte and contacts with Roxelana, the most important wife of Suleyman the Magnificent. Bona was also a spokesperson for connecting Silesia to the Crown in return for her hereditary principality Bari and Rosano, but Sigismund the Old did not support the idea and the whole project collapsed. Bona managed to also carry out tax reforms in Lithuania and agricultural products (including uniform duties of the peasants and a unit of area measurements).

Later life and widowhood

In 1539 Bona Sforza had presided, reluctantly, over the burning of 80-year old Katarzyna Weiglowa for heresy, but this event ushered in an era of tolerance, and her confessor Francesco Lismanino assisted in the establishment of a Calvinist Academy in Pińczów.

In 1544, Sigismund II Augustus was given independent authority in Lithuania, and he moved there. It was the cause of a significant weakening of power in the queen, who did not want his departure. The pair had originally entered into a conflict over her son's marriage to Barbara Radziwiłł.

On the 1 April 1548, Sigismund I the Old died, leaving Bona a widow. Their son succeeded him.

After the death of the King, Bona moved to Masovia and stayed there for eight years. Then she moved back to her native Bari.

Murder

A year after returning to the Duchy of Bari Bona Sforza was poisoned by her trusted officer, Gian Lorenzo Pappacoda. Pappacoda was acting on behalf of King Philip II of Spain, who wished to avoid repaying his sizable debts to the Polish queen. She was buried in St. Nicholas' Basilica in Bari, where her daughter Anna had a tomb made in the current Renaissance style for her remains.

Legacy

She is one of the characters on the painting Prussian Homage by Jan Matejko.

Children

Bona and Sigismund I the Old had six children:

• Isabella (18 January 1519 – 15 September 1559), was a Queen of Hungary, wife of John Zápolya,
• Sigismund II Augustus (1 August 1520 – 7 July 1572), was a King of Poland and Grand Duke of Lithuania,
• Sophia (13 July 1522 – 28 May 1575), was a Duchess of Brunswick-Lüneburg, wife of Henry V, Duke of Brunswick-Lüneburg,
• Anna (18 October 1523 – 9 September 1596), elected Queen of Poland and Grand Duke of Lithuania, wife of Stefan Batory,
• Catherine (1 November 1526 – 16 September 1583), was a Queen of Sweden and Grand Duchess of Finland, wife of John III of Sweden,
• Wojciech Olbracht, born and died 20 September 1527.

Queen Bona's gardens at the Wawel Castle