Ancient Greek writers Herodotus and Diodorus Siculus were telling the truth about the ancient Greek battles of Himera — except that they may have downplayed the role of mercenaries in Greek armies, according to new research.

In a study published Wednesday in PLOS ONE, researchers analyzed the strontium and oxygen isotope ratios of tooth enamel from ancient Greek soldiers in order to determine whether a coalition of Sicilian Greek allies saved Himera from attack in 480 BCE but not in a later battle in 409 BCE, as reported in historical accounts. This analysis provides a much-needed direct line of evidence in verifying ancient written sources on the Himeran battles and the origins of the soldiers who fought them.

The researchers found both truths and myths in the historical accounts: While 2/3 of individuals from the 480 BCE burials were non-locals, only 1/4 of individuals from the 409 BCE grave were non-locals. This confirms the historical accounts that Himera received aid in defending the city in the first battle but not the second. However, isotopic values of most non-local individuals from the 480 BCE grave are consistent with geographic regions beyond Sicily, suggesting they were hired foreign mercenaries from far-flung lands. 

The ancient Greek city of Himera, situated on Sicily's northern coast, was founded around 648 BCE; it was attacked by Carthage, an ancient Phoenician city-state in present-day Tunisia, in 480 BCE and 409 BCE. Though Carthage wasn't successful in its first attack, its forces proved too powerful for Himera in the second, which led to the destruction and abandonment of the ancient city.

The mass gravesites of these battles were found during archaeological excavations in Himera, with seven mass graves dating to 480 BCE and one mass grave dating to 409 BCE. The 132 skeletons in these graves are all males over the age of 18, some with violent trauma to the bones and others with weapons embedded in them. These clues, along with the skeletons' location on the documented battlefield site and the presence of weapons, indicate that these were the soldiers who fought in the two battles against Carthage. 

Apart from the historical accounts by Herodotus and Diodorus Siculus and the archaeological contextual evidence from the battles' mass graves, not much else is known about the origins of the soldiers. Though the written accounts say the allies from the first battle were from other Sicilian colonies, evidence from the present study suggests otherwise. 

The researchers examined tooth enamel samples from 62 soldiers — 51 from 480 BCE and 11 from 409 BCE — which represents all the individuals who had at least one tooth present for analysis. They also took samples from skeletons in the surrounding western necropolis, representing the general population of Himera, in addition to samples from local fauna, allowing the researchers to draw distinctions between locals and non-locals. 

The researchers conducted strontium and oxygen isotopic analyses of the tooth enamel from these samples. Since teeth do not remodel, or replace tissue, over time like bones, the isotopic values found in teeth are reflective of where a person was located during their childhood, which provides direct evidence into an individual's past migration and diet. 

Oxygen is reflective of the drinking water in certain areas, and so oxygen isotope values will vary across different latitudes, temperatures and precipitation amounts, said Katherine Reinberger, the lead author of the paper and a Ph.D. candidate at the University of Georgia.

"So, when you consume the water in an area during childhood," she told The Academic Times, "it becomes incorporated into your teeth, your teeth enamel, and it doesn't change over time."

Strontium values in teeth enamel are similar, but they're based on local geology rather than drinking water. 

"The underlying bedrock where you live and grow up gets broken through weathering, which gets put into the soil, which is then absorbed by the plants, which gets absorbed by the animals," Reinberger said. "So, the plants and animals that you eat have these strontium values and, therefore, your teeth will have the strontium values."

The isotopic analysis provided evidence to support the historical accounts that Himera was aided in the first battle against Carthage and that the second battle was chiefly fought by the Himerans themselves. 

However, the isotopic values for most of the non-local individuals in the 480 BCE grave suggest that Himera's assistance in the first battle came from regions beyond Sicily, suggesting that Greek tyrants in the area hired foreign mercenaries to aid them.

The study posits that the ancient Greek writers may have omitted accounts of mercenaries in the Himeran battles in an attempt to emphasize the "Greekness" of the military forces, defined by one's ability to trace their origins to Greece and a potentially important factor in determining citizenship with city-states, according to the study. 

The researchers noted that the descriptions written by Herodotus at the time "augment a distinction between Greeks and 'barbarians,' deliberately glorifying Greeks citizenry."

The glory of Greek triumph and exploit in literary sources is sometimes overstated, and the researchers point out that Herodotus and Diodorus were likely exaggerating when reporting on the Himeran battle of 480 BCE. The ancient writers claim that Himera's first battle occurred on the same day as other Greek victories, painting spectacular pictures of Greek triumph; both Herodotus and Diodorus wrote that it was "as though heaven had deliberately arranged for the finest victory and the most famous of defeats to take place simultaneously," according to the study. 

Even with these exaggerations and omissions, though, this study shows that ancient Greek writers were actually dedicated to documenting historical details and events accurately; they aren't merely literary sources, Reinberger told The Academic Times.

"As with modern sources," Reinberger said, "it's important to evaluate them with other available evidence and think critically about why certain things were emphasized or omitted."

The study "Isotopic evidence for geographic heterogeneity in ancient Greek military forces," published May 12 in PLOS ONE, was co-authored by Katherine L. Reinberger and Laurie J. Reitsema, University of Georgia; Britney Kyle, University of Northern Colorado; Stefano Vassallo, Soprintendenza BB.CC.AA. di Palermo; George Kamenov and John Krigbaum, University of Florida.