Imperial Rome Migrants ID'd

The evidence was found in the teeth of some 2,000-year-old skeletons.

The first physical evidence of individual migrants to Imperial Rome has been found in the teeth of some 2,000-year-old skeletons, says a study published in the open-access journal PLOS ONE.

The investigation took place in two Imperial-era cemeteries and showed that several individuals, mostly men and children, migrated to Rome, changing significantly their diet after their move.

It is believed that up to one million people lived in Imperial Rome, with voluntary immigrants accounting for about 5 percent of the population and slaves for up to 40 percent. However, these are just estimates, as there is no complete Imperial-era census for the city of Rome.

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"They say that all roads lead to Rome, but finding direct evidence of immigrants to the Eternal City has troubled archaeologists for decades," bioarchaeologists Kristina Killgrove of the University of West Florida, said.

To find physical evidence of human migration in Imperial Rome, Killgrove and colleague Janet Montgomery of Durham University, UK, examined skeletal remains buried at two Rome-area cemeteries during the 1st through 3rd centuries AD.

By analyzing the isotopes of the elements strontium and oxygen, it was possible to determine whether a person's tooth was formed during a time he or she was living in Rome.

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Killgrove analyzed 105 teeth for strontium isotopes, and Montgomery examined 55 of those for oxygen isotopes.

Aqueduct water and imported grain were also taken into account to assess the local isotope ranges.

"In the end, there was one female skeleton, several male skeletons, and several children whose sex could not be determined that likely were not born at Rome," Killgrove said.

At least eight individuals, five of them quite young, turned to be migrants from outside Rome, possibly from North Africa, the Alps and the Apennine Mountains in Italy.

The Colosseum in Rome. | ThinkStock

The presence of many young individuals is particularly intriguing, as most known voluntary migration was by adult men.

"Children and adolescents could have come to Rome to be educated, to become apprentices, to be married, as part of a family that migrated, or even as slaves," Killgrove told Discovery News.

The scale of slavery within the Empire was quite large.

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"Unfortunately, we can't tell from isotopes or from the way they were buried what their status was," she added.

Carbon isotopes in the teeth, reflecting carbohydrate consumption, revealed that the immigrants' diet changed significantly when they moved to Rome. They possibly adopted and adapted to the local cuisine, which included mostly wheat, legumes, meat and fish.

"This case study demonstrates the importance of employing bioarchaeology to generate a deeper understanding of a complex ancient urban center," Killgrove and Montgomery wrote.

They stressed that further isotope and DNA analysis is needed to provide more context for their findings.

Shown are the skulls of skeletons belonging to 35- to 50-year-old males who likely had migrated to Rome.

Italian archaeologists have unearthed the largest Roman water basin ever found, right in the heart of modern Rome. Lined with hydraulic plaster, the massive basin was found some 65 feet down near St. John in Lateran Basilica during the excavation of the new metro C line.

As shown in this reconstruction, the water basin was impressive. It measured 115 by 230 feet and could hold more than 1 million gallons of water.

The archaeologists unearthed a road that led to a 3rd-century B.C farm.

In the first century A.D., the basin was added to existing structures, such as water wheels, used to lift and distribute the water, as shown in this reconstruction. The basin most likely served as a water reservoir for crops as well as an area that made it possible to cope with overflows from the nearby river.

The all-woman team of archaeologists led by Rossella Rea found the exact spot where the water wheel was allocated.

The excavation also brought to light various agricultural items, such as a three-pronged iron pitchfork, and remains of storage baskets made from braided willow branches.

Lined up jars with their ends cut open were recycled as water conduits.

Used tiles were recycled to make water canals.

The tiles were inscribed with the encircled initials "TL" -- evidence that the farm belonged to a single owner.

The farm was obliterated at the end of the first century A.D., its structures, including the water basin, demolished and buried.