Pizza as we know it (dough, marinara sauce and mozzarella cheese with maybe some additional toppings) is an American invention and they were specifically called pizza pies in part to differentiate it from older "pizzas".
Prior to the very early 1900s, the Italians were making what they called pizza but it's closer to what we in the modern day would just call flatbread. In other words, just baked thin and crispy dough with some random sporadic toppings placed on it. In fact it's likely that pizza and Greek pita have the exact same origins and were originally the same thing just a flat but leaven bread.
The most common pre-1900s pizzas in Italy were just the flat bread topped with one topping with oil or fat in it such as olives, pork lard slices/Lardo, any fatty sausage, fatty fish of any type including anchovies or herring, and/or any type of cheese. After the discovery of America, tomatoes became a topping as well but it was just a topping by itself not as a pizza sauce.
Those early Italian pizzas would have looked similar to this.
Olive pizza
Lardo pizza
Then in the 1890s, the Margherita pizza came to the forefront (it may have existed in a similar form 100 years earlier but rather than in the shape of a flag, using the toppings to make the shape of a flower) but it didn't look like the modern Margherita pizza with the toppings mixed in to create an interesting flavor.
Modern Margherita Pizza
Instead the toppings were chosen solely to make the shape of the Italian flag.
So neither the ancient pizza nor even the then Margherita Pizza look like what we think of as modern pizza. Instead it was Italian-Americans in New York and New Jersey in the very early 1900s (1902-1905) that simultaneously invented what we really think of as the modern pizza, in other words matching a marinara sauce with mozzarella cheese as the topping. In New York City it was called a "pizza pie" to differentiate it from other old style pizzas being made in the city. Meanwhile in New Jersey they called it "tomato pies" (which is completely different than the Philadelphia tomato pies which are thick, risen bread topped with tomatoes and parmesan only).
Lombardi's NYC "pizza pie" from 1905
New Jersey tomato pie from Papa's one of the first
From those two simultaneously created pizza variations the NYC pizza pie and NJ tomato pie, came basically everything we think of as "pizza".