The 2,000-year-old argument over the great general Hannibal’s route through the Alps has been settled with the help of geochemists from Dublin City University.

When Carthage went to war against Rome in 218BC Hannibal masterminded a bold attack on the Romans by taking his army through a high pass over the Alps.

The bold manoeuvre and the battle that ensued has been retained by history, but for one key issue - what pass did the commander in chief of the Carthaginian army decide to take.

The answer has finally arrived thanks to some clever thinking and hard evidence in the form of poo, lots and lots of poo.

This modern day expedition was led by Prof Bill Mahaney of York University in Toronto who has had a long-standing interest in the question of Hannibal’s route, said Dr Brian Kelleher lecturer in environmental chemistry at Dublin City University.

He took part along with his PhD students Sean Jordan, Shane O’Reilly and Brian Murphy. More scientific troops joined the ranks from Queens University Belfast, the US, France and Estonia before this engagement with the question over Hannibal’s route.

Any number of mountain passes were proposed, but a suggestion 50 years ago by Sir Gavin de Beer hit on the 3,000m high Col de Traversette pass.

His thinking was based on an account written 100 years after the assault by Polybius. He collected word of mouth descriptions of the geology along the route and walked the pass to record the natural features.

This still remained hearsay until the modern day scientists got involved, with a joint effort by geologists, chemists and microbiologists, Dr Kelleher said.

The evidence was there to see if you knew where to look. Hannibal travelled with 30,000 troops, 15,000 horses and mules and for good measure 37 elephants.

They would have done what all mammals do once or more times a day, deposit faecal matter, or what the DCU team later came to call “mass animal dumpage”.

The researchers chose to look at a location were there was a convenient watering hole where men and animals would have stopped.

“We dug down three to four feet and we came across a strange looking horizon at a depth of two feet, a turned up layer that seemed to be organic,” Dr Kelleher said.

Organic material breaks down over 2,000 years but not a waxy chemical component in it, sterols.

“We did the chemical analysis and found these biomarkers for faeces. Our microbiology friends in Queens also found heightened microbes associated with animal and human faeces,” Dr Kelleher said.

This may sound like proof but not to the scientists. “This is a strong indication, and we feel it will allow for archaeological digs to prove the route but that costs money. We would hope to find artefacts to show Hannibal’s route,” he said.

It is a genuine example of brass from muck if ever there was one.