Visconti (vēskôn´tē), Italian family that ruled Milan from the 13th cent. until 1447. In the 12th cent. members of the family received the title of viscount, from which the name is derived.
Ottone Visconti, 1207–95, archbishop of Milan, was recognized (1277) as lord of the city after he had defeated the opposition of the Della Torre family, established leaders of the popular party. To keep the lordship in the family, he had Matteo I Visconti, 1255–1322, elected captain of the people in 1287. Exiled (1302–10) by the Della Torre faction, Matteo returned with the help of Holy Roman Emperor Henry VII and became imperial vicar. He established his overlordship in all Lombard cities, but Guelph opposition (see Guelphs and Ghibellines) obliged him to retire (1322) in favor of his son, Galeazzo I Visconti, 1277?–1328, who continued the struggle against popes and Guelphs. Galeazzo's son Azzone Visconti, 1302–39, consolidated the state, made peace with the pope, and increased the Milanese territories. At his death his two uncles, Lucchino and Giovanni, were proclaimed dukes.
Lucchino Visconti, 1292–1349, who in fact ruled alone, continued his predecessor's conquests, acquiring territory in Piedmont, Tuscany, and the present Ticino canton of Switzerland. The expansion of Milan aroused the other Italian states, and coalitions were repeatedly formed against Lucchino and his successors. Lucchino's brother, Giovanni Visconti, 1290–1354, took over the government in 1349. At his death the Milanese possessions were divided among his three nephews, Matteo II, Galeazzo II, and Bernabò.
Matteo II Visconti, 1319–55, was probably poisoned by his brothers, who divided his possessions. Galeazzo II Visconti, 1320–78, an able diplomat, began the transformation of his various communal lordships into an organized state. He was a patron of the arts and letters and a friend of Petrarch. At Pavia, where he held his court, he built the castle and founded the university and the library. Bernabò Visconti, 1323–85, ruled in Milan. His intrigues and territorial ambitions kept him at war with the pope, Florence, Venice, and Savoy. He died in prison, arrested by his nephew, Gian Galeazzo Visconti, 1351?–1402, the son of Galeazzo II.
Left the sole ruler of all Visconti possessions, Gian Galeazzo embarked on a systematic program of conquest, first in Venetia, then in central Italy. He withstood hostile coalitions partly by skillful diplomacy, partly by employing the best condottieri of his time. He bought (1395) his investiture as hereditary duke of Milan from Holy Roman Emperor Wenceslaus and defeated (1401) Holy Roman Emperor Rupert when Rupert sought to restore imperial rule over Italy. Gian Galeazzo's ambition was to establish an Italian kingdom, but he died of the plague while preparing a final attack on Florence, his chief enemy.
Gian Galeazzo reformed and centralized the government and promoted the arts and industries. During his reign the cathedral of Milan and the Certosa di Pavia were begun. He allied his family with the ruling house of France by marrying Isabella, daughter of John II. His daughter by a second marriage, Valentina, married Louis d'Orléans; it was through her that Louis XII and Francis I of France derived their claim to Milan in the Italian Wars.
During the regency of Gian Galeazzo's widow for her son, Giovanni Maria Visconti, 1389–1412, many cities were lost and political chaos prevailed. On reaching his majority Giovanni Maria revealed himself a dissolute and cruel ruler. He was assassinated, and the duchy passed to his brother, Filippo Maria Visconti, 1392–1447, who employed both diplomacy and force to restore the duchy. In his wars with Venice and Florence he was at first aided, then opposed, by the condottierri Carmagnola. His daughter and sole heir, Bianca Maria, married Francesco I Sforza, who became duke of Milan after the fall of the short-lived Ambrosian Republic (1447–50), set up after Filippo Maria's death.