Pizza is Italian only because of the association created in the USA. It dates back pre-Roman empire.
That is .... ehem, not correct. And shows at least a bit of great ignorance.
From the wikipedia rarticle: "Due to the wide influence of Italian and Greek immigrants in American culture, the United States has developed quite a large number of regional forms of pizza, many bearing only a casual resemblance to the Italian original."
"Traditonal Italian Pizza" will become a protected designation of origin (in Europe) under EU-law shortly. (Already is in many countries by national law.)
Pizza couldn't be made pre 18th century - only then, the tomatoe became known in Italy.
Pizza pugliese and pitta inchiusa are known since a long time before - but were made without tomatoes and had (nearly) totally different ingredients.
You are thinking of "panis focacius", I suppose. That, a flat bread baked in the ashes of the hearth, is indeed known by the Etruscans and perhaps ancient Greeks and somehow related to pizza because most probably people put some foodstuff on it.