Ian Morris, archaeologist and professor of Classics at Stanford University, joins us for a discussion on the Persian expeditions against Greece in 490-479 BC. How did the Greeks pull off a totally unexpected victory against the biggest invasion force that had ever been launched? Morris explains what the latest research and archaeology tell us about the economies, technologies, and demographics of these civilizations, as well as how these factors may have affected the result of the conflict.

Morris' most recent book is "War: What is it good for?" - a fast-paced history of the world from the Stone Age to the present that focuses on warfare, geography, and technology. In it, he makes a counter-intuitive claim: that warfare, if we look at it over many thousands of years, has actually made human societies progressively less violent.This episode focuses on the Persian wars but touches on some of the main ideas from Morris' book.