A History.com article explores the history of pizza:
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 more dense their population, and much of their living was done outdoors, sometimes in homes that were little more than a room,” said Carol Helstosky, author of “Pizza: A Global History” and associate professor of history at the University of Denver.