Preserved Poop Points Way to Hannibal's Historic Path

Signs of Hannibal's passage were preserved in poop deposits left behind by his army's horses.

The question of precisely where the historically acclaimed general Hannibal and his army crossed the Alps into Italy to defeat the Romans - during the Second Punic War, around 218 to 201 B.C. - has perplexed historians for nearly 2,000 years.

Thanks to a new study, the first evidence pointing to an answer has finally been unearthed. Clues to Hannibal's secret military route were recently discovered - not in maps or letters, but in the geologic record.

But it wasn't exactly rocks that revealed the full story. Scientists dug up signs of Hannibal's passage in preserved poop deposits, from a churned-up stretch of boggy terrain that likely served as a watering hole and toilet for the army's resting animals. [In Photos: Ancient Roman Fort Discovered]

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Even the ancient Romans couldn't agree on where Hannibal's crossing took place, and scholars around the world have debated the topic over the thousands of years since. Some proposed that the general traced a route through a narrow mountain pass called Col de la Traversette, to the southwest of Turin, Italy, but they couldn't produce any archaeological proof.

Solid evidence Chris Allen, of Queen's University Belfast, and William Mahaney, of York University in Toronto, were conducting research near Col de la Traversette that was unrelated to Hannibal. That's when the 2,000-year-old question about the general's Alps route confronted them in the shape of a mire, a waterlogged area along the mountain passage, Allen told Live Science.

It occurred to them that Hannibal's army - which included 30,000 troops, 37 elephants and an estimated 15,000 to 20,000 horses - would have needed to stop for water during their travels.

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And then, another colleague mentioned to Allen that when animals drink, they typically defecate.

"We realized if we were lucky enough in this mire to find a layer of sediment that was old enough and hadn't been disturbed, we might actually be able to find evidence of horse manure that would have been left by his army when they passed through," said Allen, an associate professor of environmental microbiology.

"A mass animal deposition"

The researchers excavated a cylindrical sample of soil called a core. They used carbon dating to establish that its layers dated back 8,000 years and examined changes - physical, chemical and microbial - that appeared in the dirt layers over time.

As they came close to the point in time when Hannibal was known to have crossed the Alps, unusual indicators appeared in the soil. The dirt was physically churned up, as though a number of animals had plodded through. Chemical analysis identified organic materials that typically inhabit a human's or a horse's gut, while DNA analysis revealed the presence of microbes associated with horse manure.

"By combining all these methods, we were able to point strongly to the fact that there was an accumulation of fecal materials at the correct date, about 2,200 years ago," Allen said. The quantity of dung appearing at that point in time hints at an animal presence that was unusual for the region, but was also likely to be associated with Hannibal, who was already known to be on the move across the Alps during that time, the authors suggested.

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Mystery solved - not with a smoking gun, but with a once-steaming pile.

The findings were published online March 8 in the journal Archaeometry.

Original article on Live Science.

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"Hannibal Crossing the Alps on an Elephant," by Nicolas Poussin (circa 1625 to 1626).

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.