GIAN GALEAZZO, the most powerful of the Visconti, became joint ruler of the Milanese territories on the death of his father in 1378 and sole ruler on the death of his uncle seven years later. He founded the cathedral of Milan, built the Certosa and the bridge across the Ticino at Pavia, improved the University of Pavia and established the library there, and restored the university at Piacenza. He was an able and economical administrator, and was reputed to be one of the wealthiest princes of his time. Am bitious to reduce all Italy under the sway of the Visconti, he conquered Verona in 1387 ; and in the following year, with the aid of the Venetians, took Padua. He plotted successfully against the rulers of Mantua and Ferrara, and finally turned his attention to Tuscany. In 1399 he bought Pisa and seized Siena. The em
peror Wenceslaus had already conferred on him the title of duke of Milan for ioo,000 florins, reserving only Pisa, and refused to take arms against him. Gian Galeazzo took Perugia, Lucca and Bologna (1400-00, and was besieging Florence when he died of the plague (Sept. 3, 1402). His sons, Giovanni Maria and Filippo Maria, were mere boys at the time of his death, and were taken under the protection of the celebrated condottiere Facino Cane de Cesale; but most of Gian Galeazzo's conquests were lost.