Visconti, a family of rulers of Milan, whose prominence began with Ottone, who in 1262 was appointed archbishop by Pope Urban IV., and waged a sanguinary struggle with the Della Torre family for mastery in the city and territory. The "struggle was continued by his nephew Matteo I., the Great (1250-1322), who, after obtaining supreme power, had to contend with a league formed against him by the Torriani and the lords of Montferrat, Piacenza, and Pavia, and was driven from Milan, but reestablished by the emperor Henry VII., who put a final end to the rule of the Torriani in 1310-'ll. Matteo extended his dominion over several places; but Pope John XXII. raised against him the Guelphs under the king of Naples, and other enemies, and he was finally constrained to resign a few months before his death. His son and successor Galeazzo I. (1277-1328) continued the warfare, and a papal force in 1323 burned the suburbs of Milan and most of the adjacent fortified castles. But the emperor Louis the Bavarian came to his rescue, and the pontifical forces, after being decimated by an epidemic, were overwhelmed in 1324. In 1327, when the emperor was crowned at Milan as king of Lombardy, he appointed Galeazzo imperial vicar.
He soon after incarcerated him at Monza, with his son Azzo and his two brothers, on the pretext of their conspiring against him with the Roman see, but released them on their paying a heavy ransom. Azzo (1302-'39) improved the condition of Milan, and his uncle and successor Lucchino annexed most of Lombardy and Montferrat, and promoted art and science. Lucchino's brother Giovanni (1290-1354) extended his rule over many cities of Tuscany. He left the government to his nephews Matteo II., Barnab6, and Galeazzo. The first soon died from poison ascribed to his two brothers. Barnab6 waged war against the papal see till 1385, when he was deposed and imprisoned by his nephew Giovanni Galeazzo, under whom the Visconti reached their highest glory. He expelled the Scalas from Verona and Vicenza, and the Carraras from Padua. For 100,000 florins he received in 1395 the title of duke of Milan from the emperor Wenceslas. He died of the plague in 1402. He was a munificent patron of art, and the founder of the cathedral of Milan. His children were minors at the time of his death.
The eldest, Giovanni Maria, became duke, but lost many of his possessions, and his cruelty and pusillanimity caused his assassination in 1412. The reign of his brother Filippo Maria was one series of wars, chiefly against the Venetians. He died in 1447, without male heirs, and Francesco Sforza, husband of his natural daughter Bianca, secured the duchy of Milan for himself and his descendants. Collateral branches of the family still exist in Lombardy.