Gorgonzola is the center of Gorgonzoal cheese making. Around Gorgonzoal, there were vast areas of pasture land, ideal for cows. During autumn, shepperds were brining their cows from the Alps to the Po Valley and they let them graze and rest around this area. The cheese made from the milk was called "stracchino/stracco" which means "tired". Later on, they called it "Stracchino di Gorgonzola".
Cheeseproduction dates at least from the 9the century, here. Originally, only autumn cheese was made. Now, there is almost no cheese produciton anymore in Gogonzola city.