[4] The duchy remained an Austrian possession until 1796 when a French army under Napoleon Bonaparte conquered it, and it ceased to exist a year later as a result of the Treaty of Campo Formio, when Austria ceded it to the new Cisalpine Republic.

[6] In the first half of the following century, his nephews and great-grandsons who came to govern Milan: Matteo I, Galeazzo I, Azzone and the Archbishop Giovanni, expanding the area of Visconti influence over the surrounding regions.

[15] The brothers Luchino and Giovanni Visconti added Bellinzona (present-day Switzerland in 1342, Parma (Emilia) in 1346 and several territories in southwestern Piedmont in 1347: Tortona, Alessandria, Asti, and Mondovì.

[16] When the last Visconti duke, Filippo Maria, died in 1447 without a male heir, the Milanese declared the so-called Golden Ambrosian Republic, which soon faced revolts and attacks from its neighbors.

[18] The Venetian republic had not abandoned its desire to expand into Lombardy and therefore entered into an alliance with Alfonso V of Aragon, King of Naples, and with Emperor Frederick III, against Francesco I Sforza and his allies.

The fall of Constantinople, conquered by the Ottoman Turks, however, endangered the structure of the Venetian possessions in the Aegean Sea and after 4 years of war the Peace of Lodi was signed in 1454.

With this document Francesco Sforza and Alfonso of Aragon were recognized respectively as Duke of Milan and King of Naples, the Republic of Venice extended its dominion up to the Adda and the Holy Italian League against the Turks was concluded.

[21]Relations between Ludovico and Ferdinand II of Aragon therefore deteriorated: Gian Galeazzo had in fact married a niece of the King of Naples, who took the side of the legitimate heir.

[24][25] Louis XII remained Duke of Milan until 1512, when the Swiss army expelled the French from Lombardy and placed Maximilian Sforza, son of Ludovico il Moro, on the Milanese throne.

[36] The government of the Habsburgs of Austria was characterized by significant administrative reforms, which the sovereigns of the Austrian house—inspired by the principles of enlightened absolutism—also introduced in their Lombard territories: for example, the rearrangement of the land register, the suppression of ecclesiastical censorship and the development of the silk industry.

[37] Following Napoleon Bonaparte's victorious campaign in northern Italy in 1796, the duchy, entrusted to an interim government junta, was ceded to the French Republic by the Habsburgs with the Treaty of Campo Formio in 1797.

[38] After the defeat of Napoleon, on the basis of the decisions taken by the Congress of Vienna on 9 June 1815, the Duchy of Milan was not restored but became part of the Kingdom of Lombardy–Venetia, a constituent land of the Austrian Empire.

At the time Lombardy had the most developed manufacturing and commercial economy anywhere in the world, making it a valuable tool for the Spanish military: an armory of paramount strategic importance.

During the 1635–1659 Franco-Spanish War, Milan sent and paid for on average 4,000 soldiers per year to the Spanish crown, with many of these men serving in the Low Countries against the Dutch States Army.