Ancient tooth debunks a 2,500-year-old claim about Greek soldiers

Greek historians like Herodotus are famous for writing down some of the first-ever Western historical records and waxing poetic about the skirmishes and wars waged throughout Ancient Greece. But just because these stories are famous, doesn’t necessarily mean they’re entirely true.

Doing isotope analysis of ancient teeth, a team of researchers from the University of Georgia has uncovered some Greek military secrets that you won’t find in history books, including the fact that soldier diversity may have been greater than the likes of Herodotus let on.

This research was published Wednesday in the journal PLOS ONE and first author Katherine Reinberger, a doctoral candidate in anthropology at the University of Georgia, tells Inverse it allows scientists to shift the study of this ancient history from society at large to individual people in a way that they “would not be able to ... without the chemical analysis.”

Here’s the background — Between 480 BCE and 409 BCE, the Greek city of Himera (located on the island of Sicily) experienced two great battles by invading Carthaginian armies. Famously, the first attack in 480 BCE was fending off with the help of non-local Greek allies (e.g. Arcadia) while the second battle was mostly fought by Greek locals and resulted in the city’s fall.

At least, this is how Herodotus and other historians of the time remembered the battle for antiquity. But Reinberger and colleagues wanted to know how it actually went down.

What’s new — To answer that question, the team analyzed the skeletal remains of the Himera soldiers. But unlike other Greek battles on the mainland, Reinberger says that these two battles were of particular scientific interest because of their mass soldier graves.

“It’s not very common to find mass graves from ancient Greek battles, so this was a unique opportunity to use isotopic research as direct evidence for soldiers’ lived experiences such as where they came from,” Reinberger says.

“Additionally, a lot of what we know about the ancient Greek military is based on armies and battles from mainland Greece ... So not only do these battles and the mass graves from them provide direct information about Greek military forces generally, they also expand what we know about the Greek military practices on Sicily.”

Why it matters — Analyzing the different isotopes found in these soldiers' teeth will help researchers not only better understand the historical accounts of these battles but could also help them understand the sociopolitical structure between Greek nationals and foreign allies or mercenaries.

“This study suggests that ancient communities were more diverse than previously thought,” says Reinberger. “The recruitment of foreign mercenaries may have provided pathways to citizenship that are not often discussed in Greek history.”

What they did — In order to piece together the battle:

• First, the researchers collected intact teeth from the two mass graves (62 in total)
• They then collected local, modern-day dental records from the area
• Finally, they completed an isotope analysis on the teeth to determine their different levels of Strontium (which accumulates in our bones via plant and soils we consume) and Oxygen (which accumulates via the water we drink) to compare to the local population

Essentially, bones from different regions will have different levels of Strontium and Oxygen and researchers can trace back these boney clues to the region these isotope levels originate from. This means that by comparing ancient teeth to modern teeth, the team can reliably determine whether or not an ancient soldier was local or not — and where they were actually from.

Using this method the team was able to confirm that the 480 BCE battle included more non-local soldiers (as many as two-thirds) than the battle of 409 BCE (which had only one-quarter non-local.) But they also discovered that historical records may have fudged the numbers a little when it came to how many foreign (i.e. soldiers from beyond the Greek territories) participated in the 480 BCE battle.

Despite history suggesting otherwise, the authors write that these foreign soldiers (who were often paid rather than voluntarily enlisted, which some Greeks disliked) “played a significant role in the fates of Greek colonies.”

Reinberger says that this is evidence that even historical texts should be looked at critically.

“Another takeaway is that ancient historians were, at least in this case, dedicated to documenting historical details and events,” she says. “However, as with modern sources of information, we need to evaluate them with other available evidence and think critically about why they may have emphasized or omitted certain pieces of information.”

What’s next — In the future, Reinberger says she’s interested in seeing how isotopic analysis could help explore other historic battles as well as what else these ancient teeth can teach us about Greek history.

“It would be amazing to have this type of information from other battles from the ancient historical record,” says Reinberger. “It would be interesting to see if there are similar levels of geographic diversity in other Greek armies or if it is unique to Greek colonies who may have already been in contact with more groups than the mainland.”

Abstract: Increased mobility and human interactions in the Mediterranean region during the eighth through fifth centuries BCE resulted in heterogeneous communities held together by political and cultural affiliations, periodically engaged in military conflict. Ancient historians write of alliances that aided the Greek Sicilian colony Himera in victory against a Carthaginian army of hired foreign mercenaries in 480 BCE, and the demise of Himera when it fought Carthage again in 409 BCE, this time unaided. Archaeological human remains from the Battles of Himera provide unique opportunities to test early written history by geochemically assessing the geographic origins of ancient Greek fighting forces. We report strontium and oxygen isotope ratios of tooth enamel from 62 Greek soldiers to evaluate the historically-based hypothesis that a coalition of Greek allies saved Himera in 480 BCE, but not in 409 BCE. Among the burials of 480 BCE, approximately two-thirds of the individuals are non-local, whereas among the burials of 409 BCE, only one-quarter are non-local, in support of historical accounts. Although historical accounts specifically mention Sicilian Greek allies aiding Himera, isotopic values of many of the 480 BCE non-locals are consistent with geographic regions beyond Sicily, suggesting Greek tyrants hired foreign mercenaries from more distant places. We describe how the presence of mercenary soldiers confronts prevailing interpretations of traditional Greek values and society. Greek fighting forces reflect the interconnectedness and heterogeneity of communities of the time, rather than culturally similar groups of neighbors fighting for a common cause, unified by “Greekness,” as promoted in ancient texts.