Right from the start, the making of pizzas tended to be largely commercial, as preparing the stuff at home requires specialized skills. Very few individuals were capable of kneading the durum wheat dough perfectly for baking in a clay oven where wood was used for lighting the fire and keeping it burning. Also, building a clay oven at home used to be an expensive affair in Naples or Rome, the two pizza hotspots in the medieval times.
As a result, pizzas, for the most part, were made in small food joints and sold directly from these outlets. As the preparation of pizzas become more fine-tuned with the introduction of machines and the addition of more ingredients, alfresco pizza stands became the most popular pizza disbursal joints. The first pizzeria, anywhere in the world, was established in Naples in 1830 which paved the way for the development of pizzeria chains in the US in the 20th century.
The first known pizzeria, Port Alba, can stake claim to popularizing the concept of a fast-food joint based exclusively around pizzas. Pizzas started becoming popular in the US towards the 2nd half of the 19th cent as the nation witnessed a massive influx of émigrés mainly from Southern Italy. In order to earn their daily bread, many of the immigrant Italians started selling pizzas along with other bakery products and groceries.
Gennaro Lombardi is believed to be the first Italian to open a pizzeria in New York City in 1905. Customers thronging to this pizzeria were mostly immigrants from Italy who were expecting to taste different varieties of pizza they were familiar with. Nevertheless, it was only after the end of WWII that GIs after having served in Italy, set upon rustling up varieties they had tasted in the Mediterranean country.
In due course, the Italian pizza which used to be embellished with mozzarella cheese, tomato slices, and herbs, was Americanized. The American pizza included large portions of beef, mutton, chicken or pork and of course generous dollops of cheese.