Dynasty that ruled the duchy of Milan between 1450 and its expulsion by a French army in 1499, and again for intermittent peri-ods in the first third of the 16th century. Its founder, Francesco (1401-1466), was the son of a successful condottiere; Francesco suc-ceeded his father and became one of the most successful professional generals of his century. The last duke of the old Visconti dynasty died without legitimate heirs in 1447, leaving only an illegitimate daugh-ter, Bianca Maria. She had been married to her father's most success-ful general, Francesco Sforza. Bianca Maria claimed the ducal throne, but the citizens of Milan reacted to the death of the last male Visconti by declaring the ducal office abolished and their old republican con-stitution restored. Facing many military challenges by predatory neighboring states, the leaders of the new republic hired Francesco Sforza to defend them, and by 1450 Sforza, having beaten off inva-sions by foreign powers, seized control of Milan and established him-self and his wife as duke and duchess. Unlike the last of the Visconti, he was an effective political as well as military leader, and his diplo-matic skill led to a revolution in the traditional power alignment of the Italian states that enabled Milan and Florence to impose on the other Italian powers a general peace treaty, the Treaty of Lodi (1454), that stabilized the internal relations of the Italian peninsula for 40 years, ending a period of frequent wars among the Italian powers.
Francesco's political and military talent was not inherited by his son Galeazzo Maria Sforza, who abused his authority to seize the property and the women of prominent Milanese citizens and was murdered in 1468. Galeazzo Maria's young son, Giangaleazzo, held the title of duke from 1476 to 1494, but real power was in the hands of his uncle, Ludovico Sforza, nicknamed "il Moro." Ludovico reduced his nephew to a mere figurehead until the nephew's death in 1494. This de facto usurpation of power enraged the young duke's in-laws, the royal family of Naples, and also the Medici leader at Florence, Piero de'Medici, who had married a Neapolitan princess. Ludovico feared that he might be attacked by a coalition of hostile Italian powers led by Naples and Florence. He sought to escape this danger by encour-aging the king of France, Charles VIII, to enforce a dynastic claim of his own to the throne of Naples. Although Ludovico probably desired nothing more than a diversionary threat of intervention, the actual re-sult was the famous French invasion of Italy in 1494, which precipi-tated a series of wars that soon drew Spain into the fighting as a rival to the French for control of Italy. This struggle ended in 1559 with a settlement that left most of the peninsula directly or indirectly in the hands of the king of Spain.
For Ludovico, the French invasion and the resulting action of Spain and several Italian allies in expelling the French from Naples initially relieved the political and military insecurity he had feared. After his nephew's death in 1494 (poisoned by the uncle, according to popular rumor), he assumed the ducal title. But the death of Charles VIII in 1498 brought to the French throne King Louis XII, who as a direct descendant of a princess of the Visconti dynasty had a hereditary claim not only to Naples but also to Milan itself. Louis XII staged a second French invasion of Italy in 1498, this time be-ginning with the conquest of Milan and the dethronement of Lu-dovico Sforza. Louis claimed the throne of Milan for himself and held Ludovico as a prisoner in France for the rest of his life. In the chaotic years that followed, Ludovico's son Massimiliano and then his younger son Francesco II enjoyed brief periods of rule at Milan whenever the Spaniards held the upper hand over the French, but when Francesco II died in 1535, the Emperor Charles V (who was also king of Spain) claimed the duchy for himself, ending Sforza rule forever and establishing Spanish control of the duchy that lasted un-til 1706.
Under the immediate successors of the first Francesco Sforza, Galeazzo Maria and Ludovico il Moro, the Sforza court at Milan be-came an important center of the courtly variety of High Renaissance culture. The Sforza rulers made their court a major center of Renais-sance music and art. The original architect of the new basilica of St. Peter at Rome, Bramante, began his career in the service of the Mi-lanese dukes, designing the cathedral in the Lombard university town of Pavia and the churches of Sant'Ambrogio and Santa Maria della Grazie in Milan. In the period of Ludovico's domination, Leonardo da Vinci painted his Last Supper in Santa Maria delle Grazie and also served the duchy as military engineer and architect.
Historical Dictionary of Renaissance. Charles G. Nauert. 2004.