[1] He was only seven years old when in 1476 his father, Galeazzo Maria, was assassinated and he became the Duke of Milan.

His uncle, Ludovico Sforza, acted as regent to the young duke, but quickly wrested all power from him and became the de facto ruler of Milan.

[2] In February 1489, Gian Galeazzo married his cousin Princess Isabella of Naples.

[5] 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's machinations …