House of Sforza
In 1447 Filippo Maria Visconti, Duke of Milan, died without a male heir; following the end of the Visconti line, the Ambrosian Republic was enacted. The Ambrosian Republic took its name from St. Ambrose, popular patron saint of the city of Milan. Both the Guelph and the Ghibelline factions worked together to bring about the Ambrosian Republic in Milan. Nonetheless, the Republic collapsed when, in 1450, Milan was conquered by Francesco Sforza, of the House of Sforza, which made Milan one of the leading cities of the Italian Renaissance.