The history of food items which may have served as the roots of modern pizza can be traced to the Greek colonies of Magna Graecia (southern Italy). Such products arguably have their first written mention in Book VII of Virgil's Aeneid:

Their homely fare dispatch’d, the hungry band
Invade their trenchers next, and soon devour,
To mend the scanty meal, their cakes of flour.
Ascanius this observ’d, and smiling said:
“See, we devour the plates on which we fed.”

In the 3rd century BC, the first history of Rome, written by Marcus Porcius Cato, mentions a "flat round of dough dressed with olive oil, herbs, and honey baked on stones"; placenta was a "sheet of fine flour topped with cheese and honey and flavored with bay leaves". Further evidence is found in Pompeii, the city "frozen in time" since AD 79, where archaeologists have excavated shops that closely resemble modern pizzerias.

Though several kinds of flat bread made with flour, often cooked with oil and spices, were familiar to ancient Romans and popular in all the Mediterranean area, they were considerably different from pizza as it is known today. The tomato was still unknown in Europe and the Indian water buffalo, whose milk is used to make the real mozzarella cheese, had not yet been imported to Campania, the area around Napoli (Naples). The crust of pizza is very similar to focaccia bread common in Italian cuisine today.

For some time after the tomato was brought to Europe from the Americas in the 16th century, it was believed by many Europeans to be poisonous (as are some other fruits of the nightshade family). By the late 18th century, however, it was common for the poor of the area around Naples to add tomato to their yeast-based flat bread, and the dish gained in popularity. Pizza became a tourist attraction, and visitors to Naples ventured into the poorer areas of the city to try the local specialty.

Until about 1830, pizza was sold from open-air stands and street vendors out of pizza bakeries. The world's first true pizzeria, Antica Pizzeria Port'Alba, opened in Naples in that period.

Modern-day pizza

Modern pizza is attributed to baker Raffaele Esposito of Naples in the Italian region of Campania. In 1889 Esposito, working in the pizzeria "Pietro... e basta così" (literally "Peter... and that's enough", established in 1890 and still operating under the name "Pizzeria Brandi"), baked three different pizzas for the visit of King Umberto I and Queen Margherita of Savoy. The pizza preferred by the Queen was very patriotic, evoking the Italian flag in its colors of green (basil leaves), white (mozzarella), and red (tomatoes). It was named Pizza Margherita in honor of the Queen. This set the standard by which today's pizza evolved and spread worldwide.

Pizza met the aristocratic taste (the King of Naples Ferdinando II of Borbone greatly enjoyed the pizza made by 'Ntuono Testa at Salita S. Teresa) and an even more decided popular favour, establishing itself as a daily course, dinner and supper of the Neapolitans.