Drone Reveals 3,000-Year-Old ‘Mega Fortress’ Dmanisis Gora In The Caucasus Mountains Is Much Larger Than Previously Thought

Conny Waters - AncientPages.com - A new drone mapping project has revealed intriguing new information about a 3,000-year-old 'mega fortress' in the Caucasus mountains, offering fascinating insights that could reshape our understanding of ancient settlement growth and urbanism.

Dr. Nathaniel Erb-Satullo, Senior Lecturer in Architectural Science at Cranfield Forensic Institute in the UK, has been investigating the site since 2018 alongside Dimitri Jachvliani from the Georgian National Museum. This year, they utilized drone technology to conduct an aerial survey of the area.

Atmospheric photo of the site at dusk, showing the location at the convergence of two gorges. 2023 excavations of the inner fortress are visible in the foreground. Credit: Nathaniel Erb-Satullo

Fortress settlements emerged in the South Caucasus between 1500 and 500 B.C., marking a significant development in regional prehistory. The Caucasus region serves as a cultural crossroads at the intersection of Europe, the Eurasian Steppe, and the Middle East and is known for its unique local identities.

Research on Dmanisis Gora began with test excavations on a fortified promontory nestled between two deep gorges. A follow-up visit during autumn revealed knee-high summer grasses had obscured much more extensive remains than initially anticipated. Beyond the inner fortress lay additional fortification walls and stone structures spread across a vast area—too expansive to fully comprehend from ground level alone.

"The drone took nearly 11,000 pictures which were knitted together using advanced software to produce high-resolution digital elevation models and orthophotos—composite pictures that show every point as if you were looking straight down.

These datasets enabled us to identify subtle topographic features and create accurate maps of all the fortification walls, graves, field systems, and other stone structures within the outer settlement. The results of this survey showed that the site was more than 40 times larger than originally thought, including a large outer settlement defended by a 1km-long fortification wall," the researchers explain.

Hillshade (top left) and orthophoto (top right) of fortress core, with plan of trench 2 excavations. For full details of excavations. Credit: Nathaniel Erb-Satullo

The research team utilized a DJI Phantom 4 RTK drone, renowned for its capability to achieve relative positional accuracy of less than 2cm and capture high-resolution aerial imagery. To ensure an accurate mapping of human-made features, the team carefully verified each feature in the aerial images for correct identification.

To analyze the site's landscape evolution, orthophotos were compared with photographs from a Cold War-era spy satellite declassified in 2013 and taken 50 years ago. This comparison offered researchers valuable insights into distinguishing recent features from older ones.

Furthermore, this method allowed researchers to assess which areas of the ancient settlement had been impacted by modern agricultural practices. All these data sets were integrated using Geographic Information System (GIS) software, enabling the identification of patterns and changes within the landscape.

"The use of drones has allowed us to understand the significance of the site and document it in a way that simply wouldn't be possible on the ground," said Dr. Erb-Satullo.

"Dmanisis Gora isn't just a significant find for the Southern Caucasus region, but has a broader significance for the diversity in the structure of large-scale settlements and their formation processes.

"We hypothesize that Dmanisis Gora expanded because of its interactions with mobile pastoral groups, and its large outer settlement may have expanded and contracted seasonally. With the site now extensively mapped, further study will start to provide insights into areas such as population density and intensity, livestock movements and agricultural practices, among others."

Oblique aerial view of outer enclosure from the north-west. Credit: Nathaniel Erb-Satullo

"A key question is whether the fortification walls, compounds, graves and smaller structures in the outer settlement were contemporary with the late-second and first-millennia BC occupation in the inner fortress. The settlement is clearly bounded by the outer fortification wall, suggesting that either the wall was built to surround a still-occupied settlement or (b) the settlement was built when the wall could still serve as a protective barrier. Still, even in the latter scenario, a prolonged chronological gap between wall and settlement construction is unlikely, as the structure and topographic expression of large first and second millennium AD settlements are markedly different," the researchers write in their study.

The obtained data provides researchers with valuable insights into Late Bronze Age and Early Iron Age societies, shedding light on the functioning of these communities.

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Following the completion of the aerial survey, Dr. Erb-Satullo has conducted additional excavations at the site. These efforts have uncovered tens of thousands of pottery shards, animal bones, and various artifacts that enhance our understanding of the society responsible for constructing this fortress.

"If the occupation of the inner fortress and outer settlement were roughly contemporary, as we suggest, this settlement would be one of the largest known in the South Caucasus Late Bronze and Iron Age.

Yet the mismatch between the substantial investment in stone architecture on the one hand, and the thinness of archaeological deposition and the rarity of surface finds on the other, suggests a form of settlement where both the density and intensity of occupation was low.

The data from Dmanisis Gora may therefore support theories about the continuing importance of pastoral mobility in Late Bronze and Early Iron Age societies  through a model of low-intensity or intermittent occupation, though more robust evidence regarding site chronology and occupation intensity is needed.

Lastly, while it remains unclear to what extent the twelfth-century BC ‘Bronze Age Collapse’ impacted the South Caucasus, material culture and settlement patterns in this region show remarkable continuity across the Bronze Age–Iron Age transition, suggesting a possible link between settlement dynamics and societal resilience. This trajectory appears to be in sharp contrast to the rest of the Near East and Eastern Mediterranean.

A complete assessment, however, requires more systematic survey of other potentially similar sites and more intensive investigation of Dmanisis Gora itself," the scientists conclude in their paper.

The study was published in the journal Antiquity

Written by Conny Waters - AncientPages.com Staff Writer