People from ancient Greece and Rome ate just bread, with wheat soup or vegetables, fish and spices. So cereals were the most important element of their daily diet, much more than today.
The Greeks used to prepare a kind of flat bread called "Atos", in fact in the excavations of Pompei (Naples) have been found samples of bread still intact left in the oven from the eruption of the Vesuvio, that happened in 79 D.C. (look at photo 1).

In ancient Rome there were two different ways to produce bread: the first was with the use of public ovens (look at photo 2), where Greek slaves produced bread for the plebs and the roman
soldiers. In return of these services, the Emperor gave them their freedom.

The other way was a kind of private production; in fact all the noble families had their own ovens to make bread. The word "focaccius" in Latin means "relevant to the fire" or means "flattened" with round shape cooked on the fire or under ashes.

photo 1 - Focaccium    2 - Public oven

With the discovery of America by Cristoforo Colombus (1492), tomatoes arrived in Spain(look at photos 3-4) , but only at the beginning of 1700 tomatoes were used on pastry disc (many experts think that pizza was born in that time).

At the beginning it was considered just a kind of flat bread, and the word "pizza" appeared in Italy around the 990 D.C., while in Naples the term appeared only around the 1535, during the marriage of Bona Sforza and Sigismondo I King of Polonia, in a illustrius party at Capuano Castel.

Many experts believe (and we share their opinion) that the birth of Neapolitan Pizza coincides with the moment in which the tomato was put on to the pastry disk, where as before it was considered just a focaccia (a kind of flat bread) or a schiacciata. We suppose that the birth of Neapolitan Pizza should be around 1720/1730, in fact they have been found some watercolours of that period where there is evidence showing the red colour of tomatoes on the pastry disc.

The first Neapolitan Pizza was called the "marinara"*, but the classical kind of pizza is the margherita.

The history of the pizza margherita, probably, began before 1847, year in which French writer Boucard mentioned it in his book "Customs of Naples", in fact Neapolitan people used to eat pizza with tomato and mozzarella. Then, on the11th June of 1889, historic date for Neapolitan pizza, Queen Margherita of Savoia convoked at the Palace of Capodimonte, in Naples, the pizza chef Raffaele Esposito to make pizza. The pizza-chef prepared three kinds of pizzas, but the Queen most liked the one with tomato and mozzarella.

From that time on, in honour of the Queen, Neapolitan people called that kind of pizza "Margherita".

photo 5 - Queen Margherita

NOTE:
* It was called Marinara (sailors' pizza) because fishermen living in Santa Lucia, area of Naples, returning from the market, used to have flat bread with tomato and the remnants of unsold fish.