Pizza has a long history. Flatbreads with toppings were consumed by the ancient Egyptians, Romans and Greeks. (The latter ate a version with herbs and oil, similar to today’s focaccia.) But the modern birthplace of pizza is southwestern Italy's Campania region, home to the city of Naples.

Founded around 600 B.C. as a Greek settlement, Naples in the 1700s and early 1800s was a thriving waterfront city. Technically an independent kingdom, it was notorious for its throngs of working poor, or lazzaroni. “The closer you got to the bay, the denser their population and much of their living was done outdoors, sometimes in homes that were little more than a room,” says Carol Helstosky, author of Pizza: A Global History and associate professor of history at the University of Denver.

These Neapolitans required inexpensive food that could be consumed quickly. Pizza—flatbreads with various toppings, eaten for any meal and sold by street vendors or informal restaurants—met this need. “Judgmental Italian authors often called their eating habits ‘disgusting,’” Helstosky notes. These early pizzas consumed by Naples’ poor featured the tasty garnishes beloved today, such as tomatoes, cheese, oil, anchovies and garlic.

Italy unified in 1861, and King Umberto I and Queen Margherita visited Naples in 1889. Legend has it that the traveling pair became bored with their steady diet of French haute cuisine and asked for an assortment of pizzas from the city’s Pizzeria Brandi, the successor to Da Pietro pizzeria, founded in 1760. The variety the queen enjoyed most was called pizza mozzarella, a pie topped with soft white cheese, red tomatoes and green basil. (Perhaps it was no coincidence that her favorite pie featured the colors of the Italian flag.) From then on, the story goes, that particular topping combination was dubbed pizza Margherita.

Queen Margherita’s blessing could have been the start of an Italy-wide pizza craze. But pizza would remain little known in Italy beyond Naples’ borders until the 1940s.

An ocean away, though, immigrants to the United States from Naples were replicating their trusty, crusty pizzas in New York and other American cities, including Trenton, New Haven, Boston, Chicago and St. Louis. The Neapolitans were coming for factory jobs, as did millions of Europeans in the late 19th and early 20th centuries; they weren’t seeking to make a culinary statement. But relatively quickly, the flavors and aromas of pizza began to intrigue non-Neapolitans and non-Italians.

One of the first documented United States pizzerias was G. (for Gennaro) Lombardi’s on Spring Street in Manhattan, licensed to sell pizza in 1905. (Prior to that, the dish was homemade or purveyed by unlicensed vendors.) Lombardi’s, still in operation today though no longer at its 1905 location, “has the same oven as it did originally,” notes food critic John Mariani, author of How Italian Food Conquered the World.

Debates over the finest slice in town can be heated, as any pizza fan knows. But Mariani credited three East Coast pizzerias with continuing to churn out pies in the century-old tradition: Totonno’s (Coney Island, Brooklyn, opened 1924); Mario’s (Arthur Avenue, the Bronx, opened 1919); and Pepe’s (New Haven, opened 1925).

As Italian Americans, and their food, migrated from city to suburb, east to west, especially after World War II, pizza’s popularity in the United States boomed. No longer seen as an “ethnic” treat, it was increasingly identified as fast, fun food. Regional, decidedly non-Neapolitan variations emerged, eventually including California-gourmet pizzas topped with anything from barbecued chicken to smoked salmon.

Postwar pizza finally reached Italy and beyond. “Like blue jeans and rock and roll, the rest of the world, including the Italians, picked up on pizza just because it was American,” explains Mariani. 

Today international outposts of American chains like Domino’s and Pizza Hut thrive in about 60 different countries. Reflecting local tastes, global pizza toppings can run the gamut from Gouda cheese in Curaçao to hardboiled eggs in Brazil.