Flickr/HrodebertRobertusPecorino Romano, a hard and salty Italian cheese, is one of Italy's oldest. The Sardinia-native cheese is made from sheep's milk, and was already a diet staple in ancient Rome, especially for soldiers thanks to its long shelf life. It's still a favorite local cheese, maybe because its recipe has barely changed since then, which we know thanks to Hippocrates, Homer, and Pliny the Elder singing its praises some 2,000 years ago. Most Pecorino Romano is made in Sardinia, and exclusively from the milk of sheep raised in Lazio and Sardinia, as well as lamb rennet paste made from animals also only from those two areas. Since its American counterpart is not made from those animals, and is in fact even often made with cow's milk, it behooves you to try the real deal in Sardinia.