When did the Duchy of Milan exist?

The Duchy of Milan existed 1395–1797. On this map it is drawn 1402–1449, 1453–1501, 1526–1539.

How large was the Duchy of Milan?

At its greatest extent drawn on this map, the Duchy of Milan covered about 43,000 km². That is the largest area the border data gives it across the years it is drawn, not necessarily its greatest extent in history.

Europe · High and late Middle Ages

Duchy of Milan

1395–1797

Italian Ducato di Milano; Lombard Ducaa de Milan. Created by imperial diploma of Wenceslaus of Bohemia on 1 May 1395 (ducal coronation 5 September 1395), when Gian Galeazzo Visconti, Lord of Milan, purchased the diploma for 100,000 florins from King Wenceslaus IV and was installed as Duke of Milan and Count of Pavia over twenty-six towns.

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Existed: 1395–1797
Shown on the map: 1402–1449, 1453–1501, 1526–1539 (3 periods)
Peak area: 43k km²
Region: Europe

Names

Italian Ducato di Milano; Lombard Ducaa de Milan.

Creation

Created by imperial diploma of Wenceslaus of Bohemia on 1 May 1395 (ducal coronation 5 September 1395), when Gian Galeazzo Visconti, Lord of Milan, purchased the diploma for 100,000 florins from King Wenceslaus IV and was installed as Duke of Milan and Count of Pavia over twenty-six towns. The Visconti had ruled Milan as lords since 1277 (the Lordship of Milan); at its height the duchy embraced the wide rural expanse of the middle Po plain.

Visconti dukes

Gian Galeazzo (1395–1402), who nearly united northern Italy and patronized the Certosa di Pavia and Milan Cathedral; Giovanni Maria (1402–1412, assassinated); Filippo Maria (1412–1447), whose death without a male heir extinguished the Visconti male line and triggered the Ambrosian Republic.

Sforza dukes

After the republican interlude (see entry 5), the condottiero Francesco Sforza — married to Filippo Maria's illegitimate daughter Bianca Maria Visconti — seized Milan and became duke in 1450, founding the House of Sforza. His descendants included Galeazzo Maria, Gian Galeazzo, and Ludovico "il Moro" Sforza, patron of Leonardo da Vinci and Bramante, whose intrigues helped trigger the Italian Wars.

Italian Wars and foreign rule

Milan became the central prize of the Franco-Spanish struggle: French occupations (1499–1512, 1515–1521, 1524–1525), a Swiss protectorate (1512–1515), Sforza restorations, and finally Habsburg rule from 1535. Milan passed under Spanish rule (1556–1707) and then Austrian rule (1707–1796) before Napoleon's annexation into the Transpadane/Cisalpine Republic (1796).

Common questions

What was the Duchy of Milan?: Italian Ducato di Milano; Lombard Ducaa de Milan. Created by imperial diploma of Wenceslaus of Bohemia on 1 May 1395 (ducal coronation 5 September 1395), when Gian Galeazzo Visconti, Lord of Milan, purchased the diploma for 100,000 florins from King Wenceslaus IV and was installed as Duke of Milan and Count of Pavia over twenty-six towns.
When did the Duchy of Milan exist?: The Duchy of Milan existed 1395–1797. On this map it is drawn 1402–1449, 1453–1501, 1526–1539.
How large was the Duchy of Milan?: At its greatest extent drawn on this map, the Duchy of Milan covered about 43,000 km². That is the largest area the border data gives it across the years it is drawn, not necessarily its greatest extent in history.

Sources

This compendium cites its sources once for the whole document rather than per territory. Its bibliography names the English Wikipedia articles for each polity as the primary basis, cross-checked against Encyclopædia Britannica, the World History Encyclopedia and the scholarship of Donald Queller, Thomas Madden and Jonathan Harris on the Fourth Crusade, whose post-conspiracy reading of 1204 this document follows. The article this entry is anchored on:

Wikipedia — Duchy of Milan en.wikipedia.org/wiki/Duchy_of_Milan

This entry was last updated 27 September 2026.

This entry was researched and drafted with AI from the sources above, and has not been reviewed by a historian. How entries are made

Text available under CC BY-SA 4.0: reuse it with a credit to The World Through Time and a link to this page. Passages drawing on the Wikipedia articles listed above are also licensed CC BY-SA 4.0 by their contributors.

Border geometry for the map itself comes from Cliopatria v0.12 (Seshat Global History Databank, CC-BY-4.0).

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