Duchy of Milan

The Duchy of Milan was a constituent state of the Holy Roman Empire, in what is now northern Italy. Created in 1395, when it included twenty-six towns and a wide rural area lying between the hills of Montferrat and the Venetian Lagoon, the Duchy was conquered by the Austrians during the 18th century War of the Spanish Succession, and in 1714 it was ceded to Austria by the Treaty of Baden. It remained an Austrian possession until 1796, when it was conquered by a French army under Napoleon Bonaparte, and ceased to exist a year later as the result of the Treaty of Campo Formio, when Austria ceded it to the new Cisalpine Republic.

After the defeat of Napoleon, the Congress of Vienna of 1815 restored many other states which he had destroyed, but the Duchy of Milan was not among them. Instead, its former territory became part of the Kingdom of Lombardy–Venetia, with the Emperor of Austria as its king. In 1866 what was left of this kingdom was annexed by the new Kingdom of Italy.