The Milanese army and the St. George's (San Giorgio) Mercenaries of Lodrisio Visconti clash in the Battle of Parabiago; Visconti is defeated.

Milan is a city in northern Italy, regional capital of Lombardy, the largest city in Italy by urban area and the second-most-populous city proper in Italy after Rome. The city proper has a population of nearly 1.4 million, while its metropolitan city has 3.2 million residents. Within Europe, Milan is the fourth-most-populous urban area of the EU with 6.17 million inhabitants. According to national sources, the population within the wider Milan metropolitan area is estimated between 7.5 million and 8.2 million, making it by far the largest metropolitan area in Italy and one of the largest in the EU. Milan is the economic capital of Italy, one of the economic capitals of Europe and a global centre for business, fashion and finance.

Lodrisio Visconti was an Italian condottiero and a member of the powerful Visconti dynasty. He is remembered as the first Italian military leader to organize a formal mercenary company, the Compagnia di San Giorgio, marking a significant development in the history of Italian warfare.

The Battle of Parabiago was fought in February 1339 near Parabiago, in Lombardy, northern Italy, between the Milanese army and the St. George's Mercenaries of Lodrisio Visconti. A renowned condottiero, the latter was an exiled member of the Visconti family then in power in Milan with a kind of triumvirate formed by Azzone and his uncles, Luchino and Archbishop Giovanni Visconti. Aiming to return victoriously to his city, he hired some 2,500 knights, mainly from Germany, and 1,000 Swiss infantry which had fought in the recent unsuccessful war of Mastino II della Scala for the hegemony in northern Italy. These units were led by Werner von Urslingen and Konrad von Landau.

February 20 is the 51st day of the year in the Gregorian calendar; 314 days remain until the end of the year.