Biogeological evidence may solve the age-old question of Hannibal’s invasion of Italy

Controversy over the exact alpine route Hannibal of Carthage followed from the Rhône Basin into Italia has raged amongst classicists and ancient historians for over two millennia.Motivation for identifying the route taken by the Punic Army through the Alps lies in its potential for identifying sites of historical archaeological significance and for the resolution of one of history’s most enduring quandaries. 

DCU PhD student Sean Jordan, Dr Shane O’Reilly (now a post-doc in MIT), Dr Brian Murphy, under the supervision of Dr Brian Kelleher of the School of Chemical Science have been collaborating with a team of international, multidisciplinary scientists to shed light on the actual route taken by Hannibal and his army. This team is led by Prof Bill Mahaney in Canada who has published extensively on the subject. The team also includes Dr Chris Allen, a microbiologist from Queens University, Belfast. The DCU contribution provides robust geochemical biomarkers that strongly suggests that an army passed by the Col de la Traversette. In this recently submitted work, they present stratigraphic, geochemical and microbiological evidence recovered from an alluvial floodplain mire located below the Col de la Traversette (~3000 m asl-above sea level) on the French/Italian border that identifies the invasion route as the one originally proposed by Sir Gavin de Beer (de Beer 1974). The dated layer is termed the MAD bed (mass animal deposition) based on disrupted bedding, greatly increased organic carbon, and the presence of deoxycholic acid and ethylcoprostanol derived from faecal matter. The presence of high relative numbers of Clostridia 16S rRNA genes suggests a substantial accumulation of mammalian faeces at the site over 2000 years ago. The scientists propose that the highly abnormal churned-up (bioturbated) bed was disturbed and contaminated by the passage of animals, feeding and watering at the site, during the early stage of Hannibal’s invasion of Italia (218 BC).

If correct, this is likely the first instance in which microbiological, organic-geochemical, mineral and geomorphological evidence is used collectively to identify a major historical archaeological site of global significance. Funding from the Irish Research Council (IRC) helped support some of the DCU scientists to meet collaborating scientists on-site, in the Italian Alps.