Gian Galeazzo was the son of Galeazzo II Visconti and Bianca of Savoy. His father possessed the
signoria of the city of Pavia. In 1385 Gian Galeazzo gained control of Milan by overthrowing his uncle Bernabò through treacherous means: by faking a religious conversion and ambushing him during a religious procession in Milan. He imprisoned Bernabò, who soon died, supposedly poisoned on his orders. After seizing Milan, he took
Verona,
Vicenza, and
Padua, establishing himself as
Signore of each, and soon controlled almost the entire
Po Valley, including
Piacenza. There in 1393, he gave the feudal power to
the Confalonieri family on the lands they already had in the valleys around Piacenza. He lost Padua in 1390 when it reverted to
Francesco Novello da Carrara. He received the title of Duke of Milan from
Wenceslaus, King of the Romans in 1395 for 100,000 florins. Gian Galeazzo spent 300,000 golden
florins 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. His residence, the Castello in Pavia, was the grandest princely dwelling in Italy. To its notable library, he added scientific treatises and richly illuminated manuscripts, many of them the fruits of his conquests. In 1400, Gian Galeazzo appointed a host of clerks and departments entrusted with improving public health. For the new system of administration and bookkeeping this established, he is credited with creating an efficient and innovative bureaucracy, with the assistance of his Chancellor Francesco Barbavara.
Conflict with France Furious at French political maneuvering that had removed
Genoa from his influence, Gian Galeazzo sought to prevent France gaining sovereignty there. King
Charles VI of France sent
Enguerrand VII de Coucy to warn Gian Galeazzo that France would consider further interference a hostile act. The quarrel was more than political. Gian Galeazzo was a devoted father to his daughter
Valentina Visconti, Duchess of Orléans. Charles VI was married to
Isabeau of Bavaria, granddaughter of Bernabò Visconti, a bitter enemy of Valentina and her father. Queen Isabeau's faction spread rumors that Valentina had an affair with Charles and that she was responsible for his mental breakdowns. Due to these machinations, Valentina was exiled from Paris in 1396, the same month as a French
Crusade army departed for Hungary. Gian Galeazzo reacted to the mistreatment of Valentina by threatening to declare war on France. After
the French-led Crusade met disaster at Nicopolis, Gian Galeazzo was strongly suspected of having informed
the Turks of the Crusaders' strength and plans.
Uniting Italy and death Gian Galeazzo had dreams of uniting all of northern Italy into one kingdom, a revived Lombard empire. Obstacles included
Bologna and especially
Florence, which joined with other local potentates in the
League of Bologna. In 1402, Gian Galeazzo launched assaults upon these cities. The warfare was extremely costly on both sides, but it was universally believed the Milanese would emerge victorious. Florentine leaders, especially the chancellor
Coluccio Salutati, worked successfully to rally the people of Florence, but the Florentines were being taxed hard by famine, disease, and poverty. Galeazzo won another victory over the Bolognese at the
Battle of Casalecchio on 26–27 June 1402. Galeazzo's dreams were to come to nought, however, as he succumbed to a fever at the Castello of Melegnano on 10 August 1402. He died on 3 September. His empire fragmented as infighting among his successors wrecked Milan, partly through the division of his lands among both legitimate and illegitimate children. == Marriage and issue ==