Gian Galeazzo Visconti (16 October 1351 – 3 September 1402), was the first duke of Milan (1395)[a] and ruled that late-medieval city just before the dawn of the Renaissance.

[8] Gian Galeazzo spent 300,000 golden florins[citation needed] in attempting to turn from their courses the rivers Mincio from Mantua and the Brenta from Padua, in order to render those cities helpless before the force of his arms.

[9] Notable are his library, housed in the grandest princely dwelling in Italy, the Castello in Pavia, and his rich collection of manuscripts, many of them the fruits of his conquests.

[11] The wife of King Charles VI of France was Isabeau of Bavaria, the granddaughter of Bernabò Visconti, and, thus, a bitter rival of Valentina and her father Gian Galeazzo.

Valentina Visconti, the wife of the Duke of Orleans and Gian Galeazzo's beloved daughter, had been exiled from Paris due to the machinations of Queen Isabeau the same month as the departure of the crusade.

[citation needed] In 1396, after the disaster of Nicopolis, Galeazzo was strongly suspected of having informed the Ottomans of the Crusaders' plans and of the size and strength of their army as vengeance for his daughter being accused of being behind the illness of King Charles VI of France, and for France's increasing control over the city of Genoa that he had attempted to hamper, for which he had been rebuked by Enguerrand VII before the battle.

They had: After Galeazzo's wife Isabelle died in childbirth in 1372, he married secondly, on 2 October 1380, his cousin Caterina Visconti,[15] daughter of Bernabò; with her he had: