Past Time

Kevin Lewis

April 01, 2023

Lineage or Legions? Explaining Imperial Rule Duration in the Roman Empire
Thomas Gray & Daniel Smith
International Studies Quarterly, March 2023 


One widely derided aspect of autocratic regimes is that they frequently feature nepotistic systems for political organization and management of power transfers, with inexperienced or unqualified individuals taking power solely because of their familial relation to the prior ruler. Such systems are thought to be more unstable and ineffective, reducing desirable outcomes for autocratic leaders, as well as the states they govern. We argue that this characterization ignores several important features of autocratic governance: rulers must constantly negotiate with other elites and rely on political networks based around loyalty and agreed-upon divisions of power, spoils, and prestige. Beneficiaries of nepotism enter office with many advantages that should make their reigns more stable and effective than those of less connected rulers. Specifically, we find evidence from the backgrounds and tenures of Roman emperors that dynastic relation to the previous ruler explains the likelihood of an emperor surviving in office without deposal as well as their effectiveness while in office. Rulers with close familial ties to their predecessor enjoyed longer rules and were associated with periods of imperial prosperity. Moreover, we also find that youth in autocratic office is a strong predictor of longevity without deposal, and that young rulers came to power owing to their dynastic relation to a predecessor.

Early dispersal of domestic horses into the Great Plains and northern Rockies
William Timothy Treal Taylor et al.
Science, 31 March 2023, Pages 1316-1323 


The horse is central to many Indigenous cultures across the American Southwest and the Great Plains. However, when and how horses were first integrated into Indigenous lifeways remain contentious, with extant models derived largely from colonial records. We conducted an interdisciplinary study of an assemblage of historic archaeological horse remains, integrating genomic, isotopic, radiocarbon, and paleopathological evidence. Archaeological and modern North American horses show strong Iberian genetic affinities, with later influx from British sources, but no Viking proximity. Horses rapidly spread from the south into the northern Rockies and central plains by the first half of the 17th century CE, likely through Indigenous exchange networks. They were deeply integrated into Indigenous societies before the arrival of 18th-century European observers, as reflected in herd management, ceremonial practices, and culture.

Entwined African and Asian genetic roots of medieval peoples of the Swahili coast
Esther Brielle et al.
Nature, 30 March 2023, Pages 866-873 


The urban peoples of the Swahili coast traded across eastern Africa and the Indian Ocean and were among the first practitioners of Islam among sub-Saharan people. The extent to which these early interactions between Africans and non-Africans were accompanied by genetic exchange remains unknown. Here we report ancient DNA data for 80 individuals from 6 medieval and early modern (AD 1250–1800) coastal towns and an inland town after AD 1650. More than half of the DNA of many of the individuals from coastal towns originates from primarily female ancestors from Africa, with a large proportion -- and occasionally more than half -- of the DNA coming from Asian ancestors. The Asian ancestry includes components associated with Persia and India, with 80–90% of the Asian DNA originating from Persian men. Peoples of African and Asian origins began to mix by about AD 1000, coinciding with the large-scale adoption of Islam. Before about AD 1500, the Southwest Asian ancestry was mainly Persian-related, consistent with the narrative of the Kilwa Chronicle, the oldest history told by people of the Swahili coast. After this time, the sources of DNA became increasingly Arabian, consistent with evidence of growing interactions with southern Arabia. Subsequent interactions with Asian and African people further changed the ancestry of present-day people of the Swahili coast in relation to the medieval individuals whose DNA we sequenced.

Monte Verde II: An assessment of new radiocarbon dates and their sedimentological context
Mario Pino & Tom Dillehay
Antiquity, forthcoming 


Monte Verde II in southern Chile is one of the most important, and debated, sites for understanding of the early peopling of the Americas. The authors present 43 radiocarbon measurements based on cores of sediments that overlie the archaeological deposits adjacent to the site. Statistical analysis of these dates narrows the deposition of the earliest sediments sealing the occupational layer to c. 14 550 cal BP. The consistency between the dates of the site's archaeological strata and its adjacent deposits allows not only consolidation of the site's chronology, but also illustration of how a multi-pronged approach can inform debates surrounding the peopling of new lands -- in the Americas or elsewhere.


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