Some time ago I wrote about the proposed certification of Real Pizza Napoletana. Marco who had at the time replied to me in the comments, he's a serious expert on the matter and is writing a book on the theme, was kind enough to send me a few pics to explain his arguments on the matter, which I happily publish below. Note: I added a few corrections after talking to Marco again.
Pizza as we know it today has its roots in the Neapolitan tradition: pizza is not an uncommon name for baked goods in central and southern Italy, but it's definition as a flat disc of dough topped with sauce and, today, almost anything coming to your mind, came straight from Napoli. Whether you believe the story about Pizza Margherita being invented by Raffaele Esposito, the pizzaiolo of Pizzeria Brandi, or if the whole thing was just a smart renaming of an existing pizza, the Neapolitan style was always a rather simple one far from today's excessive toppings. Neapolitan pizza is mainly a simple item: common toppings are the aforementioned Margherita, tomato, fiordilatte (cow milk mozzarella), and basil: marinara (a delicious one depicted above), with tomato, oregano and garlic; or simple modifications of these two.