Filippo Maria Visconti, Duke of Milan, dies in 1447 without a male heir; following the end of the Visconti line, the Ambrosian Republic is enacted.

The Ambrosian Republic takes its name from St. Ambrose, popular patron saint of the city of Milan.

Both the Guelph and the Ghibelline factions work together to bring about the Ambrosian Republic in Milan.

However, the Republic collapses when in 1450 Milan is conquered by Francesco Sforza, of the House of Sforza, which will make Milan one of the leading cities of the Italian Renaissance.