Bona of Sforza d’Aragona was born In 1494 in Italy. She belonged to a powerful family of Milano. As her father was pushed away from the rule over Milano, Isabella – mother of Bona – decided to leave the city. Her aim was to arrange the most suitable marriage for her daughter, that would bring the family political significance and help to regain lost goods. In 1518 her marriage with Polish king – Sigismund I – took place in Krakow. Only 3 years prior to that event her newly married husband lost his beloved wife – Barbara Zapolya – and was looking for a politically strong partner.

Bona was well educated and had strong character. Right after her marriage with Sigismund she tried to gain strong political position. As she could easily influence decisions of her husband, she benefited from that. She even began to form her own political party and gained – from the Pope Leon X - the right to appoint fifteen ecclesiastical benefice of very high importance. She believed that what decides about successful implementation of politics is the access to appropriate funds therefore she worked on the way of increasing the royal wealth.

The royal couple had only one male child (as Bona fell of her horse in 1527 and gave birth to the second son, however, that was still birth). Bona was desperate to ensure her son – Sigismund Augustus – right to get the rule over Poland. She used her influence, and money, to make the novelty crown her only son at the age of 10l, when Sigismund I was still alive (that is in 1530). This was the only example in Polish history when election of one of the kings took place during the life of previous king (who was recognized as heir to the throne). That event created very strong opposition against Bona. Noble brothers adopted the bill that next coronation would take place only after death of Sigismund Augustus and with their consent.

Bona Sforza lost her influence when in 1544 her son, Sigismund Augustus, left Poland to take independent rule in Lithuania. He got involved in relationship with Barbara who came from powerful Lithuanian family of Radziwill that Bona was against. In caused numerous conflicts between her and her son and resulted in accusations of Bona poisoning her daughter-in-law.

Bona was not popular among her subjects due to the fact that she was the first queen who took over politics so openly. However, she did a lot of good for Poland. Thanks to her a lot of new food products such as Italian pasta, spices, tomatoes or spinach. She also supported educational development by providing possibility of foreign studies. She built bridges, fortresses and windmills as well as developing territories wastelands.