Pizza, like so many other foods, did not originate in the country for which it is now famous. Unless you have researched the subject, you, like so many people, probably always thought Pizza was strictly an Italian creation.
The foundations for Pizza were originally laid by the early Greeks who first baked large, round and flat breads which they "annointed with oil, herbs, spices and Dates."
Tomatoes were not discovered at that time or, very likely, they would have used them as we do today.