- Italian ruling family who established themselves in the late 13th century as signori ("lords") of Milan, which they made the center of a powerful principality that by 1400 aspired to control all of central and northern Italy and perhaps even aimed at securing a royal title. The family's control of Milan grew out of the violent factional struggles between Ghibellines and Guelfs in the 13th century for control of the city's government. Authoritarian rule was first created by the rival Guelf family of Della Torre, but in 1277 they were over-thrown by a Ghibelline conspiracy led by the local archbishop, Ot-tone Visconti. Since Ottone, ruling as a bishop, could not pass his lordship on to his descendants, he arranged for his nephew Matteo Visconti to be elected capitano delpopolo, leader of the city's armed forces, first for a 10-year term and then for life. Though the Visconti were temporarily displaced by their Della Torre rivals in the early 14th century, the interruption was brief, and the family ruled Milan and a growing set of subject cities and rural districts until it became extinct in 1447 and was shortly afterward replaced by the Sforza dy-nasty. In the middle of the 14th century, the principality was ruled jointly by three Visconti brothers, with Milan and the old Lombard capital at Pavia being the two principal centers of power. The greatest figure of the dynasty was Giangaleazzo Visconti (1351-1402), who succeeded his father in 1378 and in 1385 deposed his last surviving uncle, the brutal and violent Bernabö. Having united the whole principality in his own hands, Giangaleazzo consol-idated his power, capitalized on the wealth and commercial impor-tance of Milan, and established an effective and largely beneficent in-ternal administration. But he also was ambitious to expand his territories and through shrewd manipulation of inter-city rivalries and the use of military force made himself a growing threat to the inde-pendence not only of other small states in Lombardy but also of the wealthy and powerful republics of Venice and Florence. Signifi-cantly, as he annexed conquered regions, he did not incorporate them into the territory subject to the city of Milan but ruled them in his own person, thus reducing his dependence on the political voice of the Milanese people. He brought this political development to its peak in 1395 when he purchased the title duke of Milan from the Holy Roman Emperor Wenceslas, thus acquiring a hereditary title un-der which he could solidify personal control of the whole state.Giangaleazzo's military expansion eventually united the Venetians and Florentines against him. His enemies (especially Florentine hu-manists) depicted him as an unprincipled tyrant while representing themselves as defenders of republican institutions and Italian liberty. Giangaleazzo's military power and diplomatic skill posed a serious threat to both of the great republics, and the Florentines in particular seriously feared that they would be conquered and incorporated into his territories, a fear increased by his success in taking over Pisa, Siena, Perugia, and Bologna (1398-1402).His unexpected death of plague in 1402 seemed the salvation of Flo-rentine independence. It was, however, a disaster for Milan and the large state that he had built, which rapidly collapsed and never entirely recovered under his successors. At the time of Giangaleazzo's death, both of his sons were minors. The states that had come to fear Visconti power, particularly the Venetians, quickly seized territory that Gian-galeazzo had added to his principality; in the case of the Venetians, their move to seize the easternmost provinces of the duchy marks the beginning of their direct involvement in mainland politics. Several of the subjugated cities threw off Milanese rule. The elder of Gian-galeazzo's sons, Giovanni Maria (1402-1412), was mentally deranged and proved to be so dangerous that he was assassinated. The younger son, Filippo Maria (1412-1447), was a far better ruler and managed to stabilize the duchy and restore control over the western part of his father's territories, though the Venetians kept control of the lands they had seized in the east. Filippo Maria came to be a danger to both the Venetians and the Florentines. His territories and power never equalled his father's, but he was a successful duke except for his fail-ure to produce a legitimate heir.At his death in 1447, Filippo Maria left only his illegitimate daughter Bianca Maria, whom he had married to his ablest mercenary general, Francesco Sforza. The Milanese succession crisis produced another round of wars as the citizens of Milan tried to re-establish their republican form of government while at the same time defend-ing their independence and their territories from ambitious neighbors, especially the Venetians. Eventually they had to turn to Francesco Sforza to beat off the foreign invaders, but after doing so, he seized control of the city and declared himself and his wife duke and duchess of Milan. The success of this seizure of power inaugurated a long period when the duchy of Milan was ruled by this new Sforza dynasty.
Historical Dictionary of Renaissance. Charles G. Nauert. 2004.