In the 1930s, my grandmother worked as a waitress at her sister and brother-in-law’s pizzeria. (Her name wasn’t Angelina; it was Maria.) One day, she served pizza (or “apizza,” pronounced like “ah-beetz” in Neapolitan) to a young man who worked at the nearby candy store. He asked for pepper on the pizza, so my grandmother gave him pepper—so much so that he couldn’t get enough cola to soothe his blazing palate. Perhaps he thought the heat was a harbinger of things to come, and here I am writing about my grandparents’ courtship over pizza 80 years later.

But what is pizza? Ask someone from Naples, Sicily, Argentina, New York, New Haven, Chicago, and you’ll get a different answer. Round pizza with tomato sauce and cheese—as we typically think of it—originates in Naples, Italy. The Southern Italian immigrants to the United States opened pizzerias and made pizza the world’s most favorite food. Let’s trace its history.