A team of archaeologists from Queen's University Belfast used ancient horse poop to reveal the potential answer to a huge historical mystery: When did Hannibal cross the Alps?
The commander in chief of the Carthaginian army during the Second Punic War with Rome (218 - 201 B.C.), Hannibal led his army of 30,000 men, 37 elephants and more than 15,000 horses and mules across the Alps, where he invaded Italia and forced the Roman army to submit.
Although Hannibal eventually met his defeat in Zama in 202 B.C., his military conquest is still regarded as one of the finest in history and the event nevertheless shaped the future of the Roman Republic that transformed into the Empire and subsequently led to the formation of today's European civilization.
Over the last 2,000 years, historians and academics have disagreed over the route that Hannibal took to cross the Alps. No archaeological evidence has been conclusive enough to settle the debate - until now.
The Queen's University team determined that Hannibal likely took the Col de Traversette pass, a belief that was proposed more than half a century ago by biologist Sir Gavin de Beer, but was not widely accepted by the academic community.
Using microbial metagenome analysis, environmental chemistry, geomorphic and pedological investigation, pollen analyses and numerous other geophysical techniques, the team used horse poop to reveal a "mass animal deposition" even near the Col de Traversette that dates to 218 B.C.
"The deposition lies within a churned-up mass from a 1-metre thick alluvial mire, produced by the constant movement of thousands of animals and humans," said Chris Allen, lead researcher of the study. "Over 70 percent of the microbes in horse manure are from a group known as the Clostridia, that are very stable in soil - surviving for thousands of years. We found scientifically significant evidence of these same bugs in a genetic microbial signature precisely dating to the time of the Punic invasion."
Although horse poop is a solid link to the event, if Allen and his team find additional evidence of elephants, they could settle the case for good.
The findings will be published in the journal Archaeometry.
