Today, everyone from city planners to the World Bank uses data to map the spread of urbanization. But tracking the expansion of past civilizations is trickier. Sure, historians have created snapshots of ancient societies, but no one has ever had a comprehensive record of when and where those societies emerged—until now.
Thank Yale urbanization researcher Meredith Reba. This month, she and her colleagues published a paper in the journal Scientific Data that plots 6,000 years of global, city-level population history. Their data lists not only the size of past cities, but how, when, and where they emerged. That’s a big deal—and not just for historians. “The more complete the record is, and the more accurate it is, the better we can look at these current and past relationships and try to see certain trends,” Reba says.
Reba’s isn’t the first historical record of city populations, but it is the most extensive, and user-friendly. Her team’s research builds on work by historian Tertius Chandler and political scientist George Modelski, who dedicated their careers to charting the global spread of urbanization. But Chandler and Modelski’s original data sets, published respectively in 1987 and 1970, are hard to parse—they’re tabulated, contain no geographic information, and are only available in print. Reba’s team digitized the data, cleaned it up, and assigned each of the 1,700 cities a longitude and latitude, transforming Chandler and Modelski’s unwieldy 6,000-year data set into something more useful and digestible. You can even download it for free.
Reba thinks this new set of historical data will help researchers ask fresh questions about contemporary cities.