High Quality Content by WIKIPEDIA articles! Gian Galeazzo Visconti (November 1351 3 September 1402), son of Galeazzo II Visconti and Bianca di Savoia, was the first Duke of Milan (1395) and ruled the late-medieval city just before the dawn of the Renaissance. He was the great founding patron of the Certosa di Pavia, completing at Pavia the castello begun by his father and furthering work on the Duomo of Milan. Although most famous as Signore of Milan, Gian Galeazzo was the son of Galeazzo II Visconti who possessed the signoria of the city of Pavia. In 1385 Gian Galeazzo gained control of Milan by overthrowing his uncle Bernabò through treacherous means. He imprisoned his uncle who soon died, supposedly poisoned on his orders. His first marriage was to Isabelle of Valois, who brought him the title of comte de Vertus in Champagne, rendered in Italian as Conte di Virtù, the title by which he was known in his early career. A devoted father to his daughter Valentina (wife of Louis, Duke of Orleans and mother of the famous poet, Charles of Orleans), Gian Galeazzo reacted to gossip about Valentina at the French Court by threatening to declare war on France.