Imported from Peru, tomatoes were first used on pizza in the 1550s. By the 17th century, men called pizzaioli were selling pizza with tomato sauce throughout the poor neighborhoods of Naples.
In 1889, pizza was finally concocted as we know it today, by Rafaele Esposito, a Neapolitan. In honor of a royal visit to Naples by Queen Margherita, Esposito made a round pie, with red tomatoes, green basil, and white mozzarella cheese-representing the colors of the Italian flag.
The first pizzeria in the United States, Lombardi's on Manhattan's Spring Street, was opened in 1905. But pizza was not known outside of major Eastern cities until it was popularized by GIs returning from World War II. In the decades since, the demand for pizza has grown, because it is considered a complete, inexpensive meal, one that is widely available ready-to-eat (RTE) or in the forms of quick-to-prepare grocery products.
Round is still the traditional favorite pizza shape. Deep-dish pizza, which is rectangular, is also quite popular. (Depending on region, deep-dish is also called Sicilian style, pan pizza, or simply square pizza.) French and Italian bread shapes are also widely sold, particularly in frozen form. Other varieties include stuffed pizza, which has an additional layer of crust over the toppings; and hand-held types such as rolled pizza, or pizza in a pita bread.
The favorite pizza toppings remain tomato sauce and cheese plus pepperoni, sausage, ground beef, mushrooms, peppers, and extra cheese. Some of the toppings with secondary popularity include anchovies, olives, prosciutto, and ham and pineapple. Combinations of gourmet cheeses are also quite popular.
The majority of pizza is made with white flour doughs that are cooked up either thin and flat, for round pizza; or which rise to a thickness of about an inch, for the deep dish style. Increasingly, other flours are used, including whole wheat, rice flour, corn meal, and so on, including some gluten-free formulations. What results is a range of crusts that includes whole wheat, sourdough, rice, corn, and other flavors.