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The impact of the Mongol conquests on earthen cities in Central Asia



The conquest campaigns of the Mongol Empire took place in the first half of the thirteenth century, deposing the Persianate Khwarazmian Empire and seizing its territories from Kazakhstan to the Persian Gulf and the Caucasus.

Historical accounts, such as those by Rashid al-Din (AD 1247–1318) and Ata Malik Juvaini (AD 1226–1283), describe scenes of mass destruction and violence, massacring and enslaving populations.

Based on these descriptions, the destruction has been long been suggested to be the cause of the depopulation of the region’s earthen-built cities. However, a new study by Dr Katie Campbell from King’s College at the University of Cambridge, now suggests that the depopulation rather than the destruction, is the primary reason for urban abandonment, as the remaining populations lacked the manpower and resources to maintain the earthen structures and supporting irrigation systems.

Archaeological evidence in Central Asia has found little supporting evidence of the direct destruction by the Mongols that supports the described historical narrative; however, convincing examples can be found elsewhere in parts of Russia and Eastern Europe.

Instead, previous excavations report a trend of architectural abandonment and desolation, contradicting the Mongol destruction accounts.

According to the study, abandonment events can be tracked from the 12th to the 14th century at the sites of Merv and Otrar following the Mongol conquest, with evidence of renovations, and occasionally, destruction. It is probable that the economic, political, and environmental stresses caused by the Mongol disruptions exacerbated pre-existing issues and hastened urban decline in cities which were already struggling.

According to Dr Campbell, “Both archaeological and ethnographic evidence demonstrate the importance of maintenance to earthen-built cities, and the potential for significant disruption to urban infrastructure, especially architecture and irrigation, which would occur from a decrease in population.”

“The specific properties of earthen architecture, especially the availability and affordability of mud as a building material, led to low-level reuse, and a widespread pattern of the eventual movement of cities after it was no longer possible to maintain them,” added Dr Campbell.

With the extensive economic and population disruptions caused by the conquests, the cities no longer had a sizeable population to undertake their basic maintenance, initiating the deterioration of the urban fabric that was difficult or impossible to reverse. This likely meant that earthen buildings, and sometimes entire cities, were abandoned and rebuilt across the region.

Dr Campbell said: “As the result of the archaeological findings and accompanying historical patterns, I argue that textual sources describing the destruction and desolation of cities by the Mongols should be considered within the context of patterns of construction and maintenance, which had persisted in these earthen cities for centuries.”

“Although it is likely that the Mongols caused some damage to the urban fabric, they did not literally destroy entire cities. Nonetheless, they did cause a crisis of urbanism in Central Asia, predominantly because they disrupted cycles of maintenance by sending the urban population into flight,” added Dr Campbell.

The result was a series of destroyed medieval cities that were likely destroyed by natural erosion rather than by the Mongol attacks.

University of Cambridge

Header Image: Otrar – Image Credit : Mikhail Gurulev – CC BY 4.0

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Nazca geoglyphs discovered used AI deep learning




Archaeologists from the Yamagata University have used AI deep learning to discover new geoglyphs in the northern part of the Nazca Pampa in the arid Peruvian coastal plain.

Geoglyphs in the Nazca Pampa were first identified during the 1920’s, with ongoing studies since the 1940’s revealing various figurative geoglyphs of zoomorphic designs, geometric shapes, and linear lines.

Geoglyphs can be categorised into three main types: figurative, geometric, and lineal. Archaeologists suggest that the lineal geoglyphs were created by the Nazca, a culture that developed during the Early Intermediate Period and is generally divided into the Proto Nazca (phase 1, 100 BC to AD 1), the Early Nazca (phases 2–4, AD 1 to 450), Middle Nazca (phase 5, AD 450 to 550) and the Late Nazca (phases 6–7, AD 550 to 750).

The relief type dates from the Late Formative period (400 to 200 BC), as the iconography of the geoglyphs are similar to that of Formative petroglyphs found on outcrops of rock. During this period, the region was inhabited by the Paracas Culture, an Andean people that emerged around 800 BC until 100 BC.

Since 2004, Yamagata University has been conducting geoglyph distribution surveys using satellite imagery, aerial photography, airborne scanning LiDAR, and drone photography to investigate the vast area of the Nazca Pampa covering more than 390 km2.

In 2016, the researchers used aerial photography with a ground resolution of 0.1 m per pixel to create a detailed survey of the region. Overtime, the team have identified various geoglyphs, however, the process is very time consuming, so they have adopted AI deep learning to analyse the photographs at a much faster rate.

The results of a study, published in the Journal of Archaeological Science, has revealed the discovery of four new Nazca geoglyphs using this new method by creating an approach to labelling training data that identifies a similar partial pattern between the known and new geoglyphs.

The four new geoglyphs depict a humanoid figure, a pair-of-legs, a fish, and a bird. The humanoid geoglyph is shown holding a club in his/her right hand and measures 5 metres in length. The fish geoglyph, shown with a wide-open mouth measures 19 metres, while the bird geoglyph measures 17 metres and the pair-of-legs 78 metres.

According to the study authors: “We have developed a DL pipeline that addresses the challenges that commonly arise in the task of archaeological image object detection. Our approach allows DL to learn representations of images with better generalisation and performance, enabling the discovery of targets that have been difficult to find in the past. Moreover, by accelerating the research process, our method contributes to archaeology by establishing a new paradigm that combines field surveys and AI, leading to more efficient and effective investigations.”

Yamagata University

Header Image Credit : Yamagata University

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Archaeologists study fortress in southern Georgia to understand community resilience




A team of archaeologists led by Cranfield University is conducting a detailed study of the fortress of Dmanisis Gora in the Kvemo Kartli region of Georgia.

The study is part of a project to understand why communities in the region were more resilient than other parts of the world during the transition from the Bronze to the Iron Age around 1200 BC.

Dmanisis Gora is located at the north-eastern edge of the highland zone between two such gorges. The site consists of a compact defensive core that has two defensive walls with an enclosed area of 3.7 acres.

On the plateau behind the citadel area, a third wall, extending about 1000 m from edge to edge on the plateau, encloses a much larger area of about 138.3 acres that contains numerous circular and linear stone features.

During the so-called ‘12th Century BC crisis’ and its aftermath, the majority of Middle Eastern regions underwent a period of significant turmoil characterised by the disintegration of empires, famine, crop failures, armed conflicts, and mass migration.

In contrast, the Caucasus region (consisting of present-day Georgia, Armenia, and Azerbaijan) appears to have been shielded from this tumultuous period, exhibiting only gradual transformations in material culture and patterns of settlement.

Either the region managed to entirely avoid the widespread disruption, or it did not experience the same cultural, economic, and political repercussions as other areas. This suggests that the communities in the region might have been more resilient, enabling them to withstand and adapt to the challenges in a comparatively effective manner.

Dr Erb-Satullo, from Cranfield University, said: “The key to understanding why the Bronze Age-Iron Age transition is different in the Caucasus is to study the fortress communities that dot the landscape during this period. We’re looking for clues about life in the Late Bronze Age through examining areas such as ceramics, burial rituals, farming practices, tools and social structures.”

“Given the upheaval at that time in other nearby regions, we are intrigued to find out more about one of these sites and determine what underlies their apparent resilience,” added Dr Erb-Satullo.

The project expands upon earlier pilot excavations carried out at the site prior to the pandemic, along with a thorough survey conducted in Autumn 2022 using drone-based photogrammetry. This is done by using the latest forensic technologies including isotopic analysis of animal remains, metallurgy, magnetometry and deploying drones to scan the area.

“What’s really exciting about this site is its size, preservation, and the fact that it has layers dating precisely to the years around the 12th Century BC crisis,” continued Dr Erb-Satullo. “Many fortresses are on hills which are prone to erosion. But this one has relatively flat topography, so the sediment will have built up in layers over time, helping to preserve artefacts and archaeological clues from the Late Bronze age.”

Cranfield University

Header Image Credit : BING Maps

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