Gian Galeazzo Sforza (20 June 1469 – 21 October 1494) was the sixth Duke of Milan.

Born in Abbiategrasso

Abbiategrasso

Abbiategrasso is a comune and town in the province of Milan, Italian region of Lombardy, situated in the Po valley approximately 22 km from Milan and 38 km from Pavia.- History :The town dates from Roman times...

, he was only 7 years old when in 1476 his father, Galeazzo Maria Sforza

Galeazzo Maria Sforza

Galeazzo Maria Sforza was Duke of Milan from 1466 until his death. He was famous for being lustful, cruel and tyrannical....

, was assassinated and Gian Galeazzo became the Duke of Milan. His uncle, Ludovico Sforza

Ludovico Sforza

Ludovico Sforza , was Duke of Milan from 1489 until his death. A member of the Sforza family, he was the fourth son of Francesco Sforza. He was famed as a patron of Leonardo da Vinci and other artists, and presided over the final and most productive stage of the Milanese Renaissance...

, acted as regent to the young duke but quickly wrested all power from him and became the de facto

De facto

De facto is a Latin expression that means "concerning fact." In law, it often means "in practice but not necessarily ordained by law" or "in practice or actuality, but not officially established." It is commonly used in contrast to de jure when referring to matters of law, governance, or...

 ruler of Milan for some time. In 1488, Gian Galeazzo married his cousin princess Isabella of Naples

Isabella of Naples

Isabella of Naples was the daughter of King Alphonse II of Naples by his wife, Ippolita Maria Sforza. From 1489 to 1494, she was the Duchess consort of Milan, and from 1499 to 1524 the Duchess of Bari and Princess of Rossano...

 and they had four children together: Ippolita Maria Sforza (1493-1501), Francesco

Francesco Sforza (il Duchetto)

Francesco Sforza, nicknamed Il Duchetto was the eldest son of Gian Galeazzo Sforza, duke of Milan, and Isabella of Naples.He was count of Pavia from 1491 to 1499...

 (1491-1512), Bona

Bona Sforza

Bona Sforza 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...

 (1494-1557) (who married Sigismund I of Poland) and Bianca Maria (1495-1496).

Concerning Gian Galeazzo's death in 1494 (Pavia), Italian historian Francesco Guicciardini

Francesco Guicciardini

Francesco Guicciardini was an Italian historian and statesman. A friend and critic of Niccolò Machiavelli, he is considered one of the major political writers of the Italian Renaissance...

 had this to say in his La Historia di Italia (The History of Italy):

The rumor was widespread that Giovan Galeazzo's death had been provoked by immoderate coitus; nevertheless, it was widely believed throughout Italy that he had died not through natural illness nor as a result of incontinence, but had been poisoned... one of the royal physicians...asserted that he had seen manifest signs of it. Nor was there anyone who doubted that if it had been poison, it had been administered through his uncle Ludovico Sforza

Ludovico Sforza

Ludovico Sforza , was Duke of Milan from 1489 until his death. A member of the Sforza family, he was the fourth son of Francesco Sforza. He was famed as a patron of Leonardo da Vinci and other artists, and presided over the final and most productive stage of the Milanese Renaissance...

's machinations...