Dozens of men discovered shackled in mass graves near ancient Athens were overwhelmingly local to the region rather than foreign invaders, according to new scientific research that sheds fresh light on a violent episode in the political history of Archaic Greece.
The study examined human remains from the extraordinary “Esplanada” mass burials at the Phaleron Burial Ground, where 79 adult men were found arranged in three parallel rows, many still wearing metal restraints.
Researchers used strontium isotope analysis to investigate where the men had lived and found that 64 of the 66 individuals tested — 96.9 per cent — had isotope signatures consistent with Attica.
The results challenge suggestions that the dead could have been foreign fighters or outside political forces and instead indicate that the violence was inflicted overwhelmingly on people drawn from the same regional population as others buried at Phaleron.
The findings are reported by Julianne R. Stamer, Jessica E. Rothwell, Matthew Simonton, Stella Chryssoulaki, Kelly J. Knudson and Jane E. Buikstra in the Journal of Archaeological Science: Reports.
79 men buried in rows — many still shackled
The Esplanada graves attracted international attention following their discovery in 2016 at Phaleron, the ancient port area southwest of Athens.
The burial is striking both for its scale and its treatment of the dead.
Seventy-nine adult males were deposited in three mass graves arranged in parallel rows. Many had their hands restrained with metal shackles, providing unusually direct archaeological evidence of coercion and organised violence.
Their identities have remained uncertain.
Scholars have variously interpreted the burials as evidence of competition between elites, emerging state authority and judicial punishment, political conflict, or the execution of outsiders who had become involved in struggles for control of Athens.
The new research set out to answer one of the most fundamental questions surrounding the graves: were these men Athenians and other inhabitants of Attica, or had they come from elsewhere?
Teeth reveal where the men grew up
To investigate their residential histories, researchers analysed strontium isotope ratios preserved in the men’s teeth.
Strontium occurs naturally in rocks and soils and enters the human body through food and water. Because underlying geology differs between regions, local environments can produce distinctive isotope signatures.
During childhood, strontium becomes incorporated into developing tooth enamel. Unlike bone, which continues to remodel during life, enamel preserves much of that childhood chemical signature.
By comparing the isotope composition of teeth with the expected local environmental range, bioarchaeologists can assess whether an individual probably grew up locally or moved into a region from somewhere with a different geological signature.
The researchers analysed 163 adults from Phaleron: 66 of the 79 men from the Esplanada graves and another 97 individuals from the wider cemetery population.
The results were strikingly consistent.
Of all 163 individuals examined, 156 — or 95.7 per cent — displayed strontium isotope values compatible with the local signature.
Among the Esplanada men specifically, 64 of the 66 tested, or 96.9 per cent, were classified as local to Attica.
Statistically, the researchers found no significant difference between the residential histories of the men in the mass graves and those of the wider population buried at Phaleron.
Foreign invader theory dealt a major blow
The findings make an explanation involving a large group of foreign invaders considerably less likely.
Instead, the men appear to have emerged from essentially the same local population as other people buried at Phaleron.
That distinction could have important consequences for interpretations of their deaths.
Rather than representing outsiders captured during an invasion or other external military action, the mass burial increasingly points towards violence generated within Archaic Attic society itself.
The researchers argue that the results “contextualize and humanize” the men, demonstrating that those subjected to the distinctive and apparently violent burial treatment did not have substantially different residential histories from their contemporaries in the surrounding cemetery.
The evidence therefore strengthens interpretations connecting the graves to internal political or social violence.
A violent period in the emergence of Athens
The Esplanada graves date to a transformative period in the history of Athens and Attica.
Archaic Athens experienced intense political competition as institutions, laws and ideas about citizenship and collective authority evolved.
Some researchers have interpreted the Phaleron burials as evidence of the increasing ability of an emerging political community or state to exercise organised authority over individuals — including the power to punish and execute them.
Under this interpretation, the graves could reflect a transition in which punishment increasingly became a matter for public institutions rather than private individuals or families.
Other scholars have reached almost the opposite conclusion.
Rather than demonstrating the successful emergence of institutional authority, the killings may reveal a society that still lacked sufficiently established institutions to prevent violent political struggles.
Determining whether the dead came from outside Attica or from its own population is therefore crucial to evaluating competing explanations.
The isotope evidence now strongly favours a predominantly local origin.
Were the men involved in an ancient political coup?
Exactly who the shackled men were remains unresolved. The graves have inevitably prompted attempts to connect them with known episodes of political upheaval in early Athens. Researchers have considered whether they might represent political actors involved in struggles for power, members of an elite faction, rebels, criminals or people caught up in a broader confrontation.
The isotope results cannot identify their political loyalties, social status or the precise circumstances of their deaths.
Nor does being isotopically “local” necessarily mean that every man was born within Athens itself. Strontium isotope analysis identifies compatibility with a geological region rather than providing an ancient home address.
What the results do demonstrate is that almost all the tested men had residential histories consistent with Attica and were not isotopically distinguishable as a group from the wider Phaleron burial population.
That makes the possibility that they represented a predominantly foreign force much harder to sustain.
Wider cemetery was also overwhelmingly local
The research produced another important result beyond the mystery of the shackled men.
The wider population buried at Phaleron was itself overwhelmingly local.
Researchers had expected greater evidence of mobility because connections and movement throughout the Aegean were increasing during the Archaic period.
Yet only seven of the 163 people analysed produced isotope signatures outside the identified local range.
The findings therefore provide bioarchaeological support for evidence suggesting relatively limited migration into Attica during this period, despite growing economic and cultural connections elsewhere in the Greek world.
In other words, goods, ideas and political influences may have circulated extensively through the Aegean while much of Attica’s population remained comparatively rooted in the region.
Science narrows a 2,500-year-old mystery
The discovery does not establish why the 79 men were killed or who ordered their deaths.
But it removes one major piece of uncertainty surrounding one of the most dramatic archaeological discoveries from Archaic Greece.
The men buried together at Phaleron were not, on the available isotope evidence, predominantly strangers arriving from distant territories.
They were overwhelmingly people whose childhood residential histories were compatible with those of the surrounding population.
For archaeologists trying to reconstruct the political violence that accompanied the emergence of ancient Athens, that changes the focus of the investigation.
The evidence increasingly points not towards an attack by outsiders, but towards conflict from within Attica itself — a violent episode in which local men were restrained, killed and placed together in graves that would remain hidden for more than two millennia.
Sources : ScienceDirect – 10.1016/j.jasrep.2026.105952
