Romans brought mules north into Central Europe, study shows

"The breeding of mules must have been a lucrative economic activity, considering that in the Roman assemblages studied by us, every sixth equid was a mule."
“The breeding of mules must have been a lucrative economic activity, considering that in the Roman assemblages studied by us, every sixth equid was a mule.” Photo: Dario u, public domain, via Wikimedia Commons

The Romans were the first to bring mules to Central Europe, researchers have found.

Mules, which are horse-donkey hybrids, have been valued in the Mediterranean basin since the Iron Age.

They became integrated into the animal world north of the Alps in the course of Romanization, researchers reported in the Journal of Archaeological Science.

Before their arrival near the end of the first century BCE, horses were the only riding animals used by the Celtic peoples there. Those in Celtic settlements in the northern Alpine foothills exclusively bred horses.

Their horses, highly prized as “animals for the elite”,  were chiefly used for military operations.

When Romans pushed into the regions north of the Alps shortly before the birth of Christ and settled there, they took mules with them from the Mediterranean area.

The findings were a result of genetic analyses conducted by a research group from the ArchaeoBioCenter at Ludwig Maximilian University in Munich, the nearby State Collection for Paleoanatomy, and the University of Vienna in Austria.

Mules were esteemed by the military as pack and work animals. Romans valued the horse-donkey hybrids, particularly for their strength, endurance, and sure-footedness in mountainous terrain. In addition, mules could survive on less valuable feed and are more resistant to diseases than horses and donkeys.

Before now, the beginning of the economic and military significance of mules for the peoples in settlement regions north of the Alps was fraught with uncertainties.

Even for experts, it is tricky to distinguish the archeological remains of Equidae – that is to say, horses, donkeys, and their hybrids, mules and hinnies – from each other.

Most skeleton parts of animals from this family are just too similar.

The researchers investigated ancient DNA from more than 400 equids from one Celtic and seven Roman settlements in the northern provinces of the Roman Empire, Raetia, Noricum and Upper Pannonia – today’s southern Germany, eastern Switzerland, and Austria – from the 1st century BCE and the 1st to 5th centuries CE.

They compared the genetic analyses with the results of traditional methods of species identification – examination of the morphology, shape, and size of mandibular teeth and particular bones. Remains of mules were found only in the Roman settlements.

Their investigations revealed that mules could be identified not only from their ancient DNA, but also through the characteristics of their premolar teeth in particular.

“However, the secure identification of the horse-donkey hybrids is contingent upon access to comprehensive reference collections of equid skeletons, so that researchers can compare them against archeological finds,” said Joris Peters, who is the director of the State Collection for Paleoanatomy in Munich and the chair of paleoanatomy at Ludwig Maximilian University.

“DNA is not always sufficiently well preserved in archeological material to be able to identify animals with certainty. Building up comprehensive natural history collections is therefore also essential for research into past cultures.”

The authors said their findings reveal a major shift in the composition of equid herds initiated with the Roman conquest, when for the first time mules and occasionally even a donkey arrived in the region.

“The breeding of mules must have been a lucrative economic activity, considering that in the Roman assemblages studied by us, every sixth equid was a mule,” they said in their just-published paper.

Further east, in continental central Europe, however, such efforts may have been thwarted due to the climatic conditions specific to our study area.

“In this respect, geochemical analyses of mules exploited in Roman military service illustrate that the animals first grew up in warmer regions before they were brought over the Alps, which confirms that hybridization had taken place in breeding centers south of the Alpine divide.

“It remains to be seen, however, whether this stayed the only option to the military once the army units became stationary, and controlling the borders towards the so far unoccupied territories of Central Europe became their main task.

“Future research will thus have to deal with the question of whether there were local breeding efforts or even, at times, hybrid imports from Gaul or from other parts of the Roman Empire.”

Ancient DNA refines taxonomic classification of Roman equids north of the Alps, elaborated with osteomorphology and geometric morphometrics,
Muhammad Bilal Sharif, Azadeh Fatemeh Mohaseb, Michaela Isabell Zimmermann, Simon Trixl, Konstantina Saliari, Günther Karl Kunst, Thomas Cucchi, Sigrid Czeika, Marjan Mashkour, Ludovic Orlando, Katrin Schaefer, Joris Peters, Elmira Mohandesan
Journal of Archaeological Science, Volume 143, 2022, 105624, ISSN 0305-4403,

The study, published under a Creative Commons License, can be read here.

Latest research and information from the horse world.

Leave a Reply

Your email address will not be published.