Using declassified photos from Cold War-era spy satellites, researchers have identified hundreds of previously undiscovered ancient Roman forts in Iraq and Syria. Their findings, published last week in the journal Antiquity, are changing long-held assumptions about the Roman military’s role in the area.
Previously, historians knew about a smaller number of the forts. Dating to between the second and sixth centuries C.E., they were thought to function as defensive military posts. The new research upends these ideas, suggesting the forts were more likely built to support trade and travel.
In the 1920s and 30s, French archaeologist Antoine Poidebard discovered 116 of the forts by photographing them from a biplane. These forts appeared to form a defensive wall that ran from north to south along an eastern boundary of the empire. Poidebard thought this wall likely acted as a Roman military barrier against invaders.
Since then, “historians and archaeologists have debated the strategic or political purpose of this system of fortifications, but few scholars have questioned Poidebard’s basic observation that there was a line of forts defining the eastern Roman frontier,” write the researchers.
The team analyzed declassified images from satellites connected to two United States military programs: Corona, which ran from 1960 to 1972, and Hexagon, which ran from 1971 to 1986. The images from Corona were declassified in 1995, while those from Hexagon were released in 2011, per CNN.
Based on the photos, the researchers realized that the 116 forts Poidebard found were just a small part of the ancient infrastructure. In total, they identified 396 new fortified structures—which didn’t just run north to south. They were spread out in a larger cluster that also ran east to west, which doesn’t support the notion that they protected an eastern border.
Instead, the researchers think the Romans built the forts to enable safe, peaceful trade across the landscape, perhaps “offering water to camels and livestock, and providing a place for weary travelers to eat, drink and sleep, thereby playing a critical role in bringing east and west together,” per Antiquity.
Casana thinks his team’s analysis holds critical lessons for the present day. “Historically, as an archaeologist, I can say that there have been many attempts by ancient states to build walls across borders, and it has been a universal failure,” he tells CNN. “If there’s any way that archaeology contributes to modern discourse, I would hope it is that building giant walls to keep people out is a bad plan.”
These photos are also a valuable snapshot of the area in the 1960s and 70s, “[preserving] a high-resolution, stereo perspective on a landscape that has been severely impacted by modern-day land-use change,” Casana tells the Guardian’s Caroline Davies. “Many of the likely Roman forts we have documented in this study have already been destroyed by recent urban or agricultural development, and countless others are under extreme threat.”
Rocco Palermo, an archaeologist at Bryn Mawr College who was not involved in the study, tells Science’s Andrew Curry that in-person excavations are necessary to support the new research. “We need to put shovels in the ground,” he says.
Unfortunately, conflict in the region makes in-person analysis difficult. Still, “this is an important stepping stone for future research, once things get stable in the region.”