How military technologies spread across the ancient and medieval worlds

A new analysis spanning 10,000 years of history and ten major world regions has identified world population size, major technological advances, and geographical connectivity as key drivers of the evolution of military technology prior to the Industrial Revolution.

An international team of researchers has published their study in the journal PLOS ONE, in which they look for the mechanisms that drove innovation, spread, and adoption of new military technologies during ancient and medieval times. They found that the strongest influences on the evolution of military technology came from world population size, the connectivity between geographical areas and advances in critical technologies such as iron metallurgy or horse riding. Meanwhile, state-level factors such as the size of the population, the territory, or the complexity of governance seem not to have played a major role.


“We had two goals for this study,” principal investigator Peter Turchin points out. “First, we wanted to draw a clear picture of where and when military technologies appeared in pre-industrial societies. Second, we intended to find out why important technologies were developed or adopted in certain places.”

For their analyses, the researchers used Seshat: Global History Databank, a large and constantly growing collection of historical and archaeological data from across the globe. To date, Seshat has assembled around 200,000 entries from more than 500 societies, spanning 10,000 years of human history.

Spread of horse-mounted Cavalry – image courtesy PLOS ONE

“Seshat is a goldmine for the study of cultural evolution,” says Turchin, who initiated and further developed the database together with a team of anthropologists, historians, archaeologists, mathematicians, computer scientists, and evolutionary scientists. To explore this data, the authors applied innovative quantitative methods of mathematical modeling and statistical analysis.


“Some military inventions had cascading effects on cultural and social evolution,” explains Turchin, who conducted the data analyses in this study. “The invention of bit and bridle, for instance, made it easier to control horses, which led to advances in weapons or the appearance of mounted archers and knights, which again made it necessary to build better fortifications. According to our study, this bundle of military technologies was one of the most important factors leading to the rise of mega-empires and of world religions like Christianity, Buddhism, and Islam during the first millennium BCE.”

Turchin and colleagues define a ‘mega-empire’ as a society supporting tens of millions of inhabitants and covering millions of square kilometers of territory, which they say began to appear in different parts of Europe and Asia as part of a process of growing social complexity driven by the connection – and competition – between states with increasingly advanced and dangerous technology.

The scientists also found strong signs of the importance of agricultural productivity. “A certain level of food production may have been necessary for the subsequent development of new war technologies,” says co-author Dan Hoyer, who leads and organizes Seshat data collection. “To explore the role of agriculture for the evolution of military technology in more detail would be an interesting next research step.”

Spread of iron metallurgy – image courtesy PLOS ONE

Seshat was developed to distinguish cause and effect in theories of social evolution. “Good data and methods like the ones we developed here offer a fresh perspective on a multitude of open questions, theories, and controversies in various fields, ranging from archaeology, to history, to the social sciences,” emphasizes Turchin. Furthermore, studies like this can contribute to a general understanding of what makes a society thrive or how to recognize early signs of deterioration and societal collapse.

“A fundamental understanding of social dynamics is not only of academic interest,” says Turchin who works with a team at CSH on Social Complexity and Collapse. “To understand what leads to social transformation, and being able to identify the ‘tipping points’ that lead to either resilience or catastrophe, is crucial for all of us, especially today,” he concludes.

The authors view this study and their methodology as a significant first step towards better understanding of the drivers of both military technological advancement and technological advancements in general. They hope that future research will refine and extend this work; for example, by exploring the development of various technologies impacts equality and public well-being.


The authors add: “In this paper we set out to study the processes driving the evolution of military technology in the pre-industrial world. We were surprised to find that the size and internal complexity of states had very little impact. Instead, increased connectivity – and growing conflict – between societies across great distances, as well as the adoption of certain key innovations like cavalry and iron metallurgy, emerged as key drivers of military technological evolution.”

The article, “Rise of the war machines: Charting the evolution of military technologies from the Neolithic to the Industrial Revolution,” by Peter Turchin, Daniel Hoyer, Andrey Korotayev, Nikolay Kradin, Sergey Nefedov, Gary Feinman, Jill Levine, Jenny Reddish, Enrico Cioni, Chelsea Thorpe, James S. Bennett, Pieter Francois, Harvey Whitehouse, appears in PLOS ONE. Click here to read it.

Top Image: Corpus Christi College MS 26


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