Dozens of new Roman army camps from two millennia ago have been discovered in northern Spain.
Experts used remote sensing technology to discover the 66 camps of different sizes, which the Romans would have used to train and take refuge during one of their most infamous conflicts: the conquest of Hispania.
Researchers can identify the original location of the camps through crop marks, depressions, and faint physical traces on the ground that appear in satellite images.
The 66 camps were probably active towards the end of the 200-year battle for the Iberian Peninsula (the mass formed by Spain and Portugal), which the Romans knew as “Hispania”.
Analysis of the 66 camps near the Cantabrian Mountains in northern Spain shows that the Roman army had a larger presence in the region than previously thought during the later stages of the bloody battle.
Roman occupation progressively progressed from the south of the peninsula to the north over two centuries, from 220 BC to 19 AD.
Roman military presence in northern Castile. The first 25 sites included in this new study are colored red
Roman military presence in León. The image shows the location of the other places in red, numbered 26 to 66.
“We have identified so many places because we have used different types of remote sensing,” said study author João Fonte of the University of Exeter.
“Airborne laser scanning gave good results at some of the more remote locations, as it showed very good ground movements.
‘Aerial photography worked best in low-lying areas for crop mark detection.
“The remains are from the temporary camps that the Roman army established when moving through hostile territory or when maneuvering around its permanent bases.
“They reveal the intense Roman activity at the entrance of the Cantabrian Mountains during the last phase of the Roman conquest of Hispania.”
The color-coded image shows the progression of the Roman conquest of the Iberian Peninsula (known as Hispania by the Romans), from 220 BC. The conflict ended in 19 BC when Augustus, the first Roman emperor, annexed the entire peninsula to the Roman Empire.
The new sites are located in the foothills of the 180-kilometer-long Cantabrian mountain range, which stretches from west to east along the upper part of Spain.
The conflict between Romans and natives focused on the Cantabrian Mountains in the late 1st century BC.
This suggests that soldiers cross between lowlands and highlands, using ridges in the mountains to stay out of place and give themselves more protection.
The fact that there were so many army camps in the region shows the “immense logistical support” that allowed the soldiers to conquer the area.
Roman soldiers allegedly attacked indigenous groups from different directions, according to the team.
The camps were used to facilitate movement to remote places and to help soldiers stay in the area during the cold winter months.
Some of the camps may have housed soldiers for weeks or months, and others overnight.
The aim of its occupation was to expand the empire and to be able to exploit natural resources such as tin and gold.
Roman military sites in the northwest of the Iberian Peninsula according to their discovery or date of publication. The main administrative units mentioned in this document are Galicia (GAL), Asturias (AST), Castilla y León (CyL), Cantabria (CAN) and northern Portugal (POR).
According to experts, only a handful of Roman military sites were known in northwestern Iberia.
But since the beginning of this century, a “digital revolution” and the potential of remote sensing techniques have fueled the discoveries of new fields.
In the last five years, remnants of fields have been reported in the softer topographies of central and western Galicia, as well as in northern Portugal.
The fields and their temporary occupations used to leave fragile and subtle traces on the surface.
The ditches or earthen and stone walls that protected these fortifications have been filled and flattened.
But a combination of different remote sensing images and fieldwork shows the perimeter shape of military fields, often a rectangle like a playing card.
For this study, the experts analyzed aerial photography and satellite imagery, created 3D terrain models from LiDAR data, and used drones to create detailed maps of the sites.
This included resources from the Spanish National Geographic Institute (IGN) and geoportals such as Google Earth or Bing Maps.
Precise locations allowed archaeological fieldwork projects to be carried out, providing new information about Roman camps in this region.
Archaeological features in the north of southern Castile-Cantabria, as seen in the satellite images provided by Google Earth
Aerial photographs of the Tortolondro camp (black) (A), the Roman road (white) and the camp (black) in Quintanilla de Riofresno
The investigation will continue so that experts can examine the relations the Romans established with the indigenous communities, called Vaccaei, Turmogi, Cantabria, Asturias and Callaeci, according to Greek and Latin sources.
The team is currently developing a project to catalog and document all the Roman camps in the province of León using drones, in order to better understand their structures or the evolution of their state of conservation.
Work is also continuing in the northern city of Burgos and the nearby city of Sasamón, including a study of the settlement of Cerro de Castarreño and its conquest in the 1st century BC.
The findings have been shared with cultural and heritage organizations so that they can be protected in the future.
The research has been published in the journal Geosciences.