Economic Diversification Supported the Growth of Mongolia\u2019s Nomadic Empires

Shevan Wilkin,Richard W Hagan,Ricardo Fernandes,Alicia Ventresca Miller,Robert N Spengler,William T T Taylor,Patrick Roberts,Madeleine Bleasdale,Erdene Myagmar,Jana Zech,Nicole Boivin,Bryan K Miller,S Ulziibayar

doi:10.1038/s41598-020-60194-0

Abstract

Populations in Mongolia from the late second millennium B.C.E. through the Mongol Empire are traditionally assumed, by archaeologists and historians, to have maintained a highly specialized horse-facilitated form of mobile pastoralism. Until recently, a dearth of direct evidence for prehistoric human diet and subsistence economies in Mongolia has rendered systematic testing of this view impossible. Here, we present stable carbon and nitrogen isotope measurements of human bone collagen, and stable carbon isotope analysis of human enamel bioapatite, from 137 well-dated ancient Mongolian individuals spanning the period c. 4400 B.C.E. to 1300 C.E. Our results demonstrate an increase in consumption of C4 plants beginning at c. 800 B.C.E., almost certainly indicative of millet consumption, an interpretation supported by archaeological evidence. The escalating scale of millet consumption on the eastern Eurasian steppe over time, and an expansion of isotopic niche widths, indicate that historic Mongolian empires were supported by a diversification of economic strategies rather than uniform, specialized pastoralism.

Highlights

Empires are, inherently complex and, by definition, extend their control over multiple societies, cultures, and economies, as well as heterogeneous landscapes[8,9,10]
Crop surplus has traditionally been viewed as an essential component of stable political entities and complex imperial food production and procurement systems are often over-simplified by historians and archaeologists, leading to their characterization as single-resource systems
To further confirm that the increased δ13C values in human bone collagen and tooth enamel through time is a product of the consumption of crops rather than changing availabilities of baseline C4/C3 plant ratios or the availability of samples in different local environments, we developed a Bayesian model to produce a C4 dietscape, representing estimates of spatial distribution of C4 plants based on per capita caloric consumption (See SI for detailed discussion)

Summary

Introduction

Inherently complex and, by definition, extend their control over multiple societies, cultures, and economies, as well as heterogeneous landscapes[8,9,10]. L.) and barley (Hordeum vulgare L.) – and C4 plants on the other – including millets and maize (Zea mays L.) – can be tracked through the bone collagen and bioapatite of humans relying on these resources and/or the animals feeding off of them[32]. We use stable carbon isotope analysis of human tissues to directly test whether, in line with some previously published archaeobotanical and historic evidence, the Xiongnu and Mongol empires relied quite significantly on millet-based agricultural systems. We present δ13C and δ15N analysis of human bone collagen and δ13C and δ18O analysis of human tooth enamel bioapatite from 137 previously-excavated individuals from across Mongolia dated to between c. We present δ13C and δ15N analysis of human bone collagen and δ13C and δ18O analysis of human tooth enamel bioapatite from 137 previously-excavated individuals from across Mongolia dated to between c. 4400 B.C.E. and 1375 C.E. in order to directly assess changing diets through the region’s key imperial transitions

Objectives

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Results

Conclusion