Where did Hannibal cross the Alps – Col de la Traversette (updated)

15 months ago,  I wrote an extensive article about whether Hannibal may have crossed over the Col de la Traversette in 218 BC on his way to attack the Roman army in Italy. It was based on considerable coverage in the world’s media during April 2016 of the results of core samples taken by Professor Bill Mahaney and his team on the Traversette. The presence of large quantities of bacteria in the soil samples seemed to indicate that a large herd of horses had crossed over the Col de la Traversette 2,200 years ago. around the same time as Hannibal crossed the Alps. However, I concluded in my article that the bacteria was probably caused by thousands of mules that transported bags of salt over the Traversette in medieval times between 500 and 1000 years ago. The weight of the salt would have caused the mules to sink in the soft ground near the summit of the Traversette and as a result churn up deeper older soil from over 2,000 years ago and make it appear that the churned up layer was generated in Hannibal’s time and not much more recently. After discounting the Traversette, I then looked at whether Hannibal may have crossed the Col du Clapier or the Petit Saint Bernard instead. I concluded that Hannibal crossed over the Petit Saint Bernard as this was the main route used by the local Gallic tribes at that time and because there are many landmarks on the Petit Saint Bernard that correspond with accounts of the crossing written by historians shortly after it. My blog posts about Hannibal and his crossing the Alps were just 3 in about 150 blog posts I have wrote over the last 3 years about my travels around Europe. But I have been amazed at the reaction as those 3 posts about Hannibal have had more hits than all my other blog posts put together. The story of Hannibal crossing the Alps with his army which included 37 elephants, obviously still resonates to this day and the mystery as to the exact route that he took only adds to the intrigue.

Col de la Traversette. Source : Channel 4

My original article about the Col de la Traversette was wrote in April 2017 but then in February 2018, a documentary was shown on Channel 4 in the UK about Bill Mahaney and his team’s findings on the Col de la Traversette. The documentary was called “Hannibal’s Elephant Army : The New Evidence” and shown at 8.00pm on Sunday February the 25th, which is a prime-time slot on UK TV. Despite being shown at the same time as the new series of Top Gear on BBC2,  it was still watched by over 1.3 million people in the UK, which is a considerable viewership for a documentary. In March 2018, the documentary was shown on French and German TV with subtitles and also attracted an audience of millions. As a result of this documentary, hits to my website have exploded and I am now No. 2 on Google for “hannibal col de la traversette” behind Wikipedia and ahead of such esteemed publications as The Guardian, New York Times and others that printed articles about Professor Mahaney’s research in April 2016. So seeing as this documentary has been responsible for so many hits to my website, I thought I would do a review of it.

Screenshot from Hannibal’s Elephant Army – The New Evidence. Source : Channel 4

The documentary was mostly filmed in the summer and autumn of 2017 and followed Professor Mahaney and his team as they returned to the Col de la Traversette , a year after after his groundbreaking research was published in April 2016. The whole documentary is 47 minutes long and was produced by Lion Television for Channel 4. Lion Television is one of the UK’s leading television production companies with bases in London, Scotland and New York. They previously produced the excellent Pilgrimage by Simon Reed for the BBC and also a series of programs about the Adelphi hotel in Liverpool called Hotel also for the BBC. Their documentary about “Hannibal’s Elephant Army” is very good and really explains the difficulties Hannibal and his army would have faced crossing the Alps as well as covering the new evidence that Professor Bill Mahaney and his team discovered on the Col de la Traversette.

Professor Bill Mahaney of York University in Toronto. Source : Channel 4.

The main character in the documentary was Professor Mahaney and it was great to see him being interviewed and hear him speak after having read most of the research papers he has wrote. This man has climbed more mountain passes in the French Alps than almost anyone else alive today. His quest to find a pass that best matched the historical records of Hannibal’s crossing led him to settle on the Col de la Traversette in the mid 90’s. Since then, he has led many expeditions and published numerous papers about the Traversette pass. Most of his work would have been known only to fellow geologists and some Hannibal enthuaiasts but that all changed in April 2016, when practically every major newspaper in the world reported that he had found new evidence that Hannibal had crossed over the Traversette.

Screenshots showing the depth to the so-called “Hannibal layer”. Source : Channel 4.

The documentary included a number of photographs which were taken between 2013-2015 showing excavations that Professor Mahaney and his team had carried out on previous expeditions. The photos show a layer of disturbed soil between 40 and 50 cm beneath the surface at a location on the French side of the Col de la Traversette. When samples from the disturbed layer were analysed using carbon dating they were found to all be from between 2,000-3,000 years ago. The median date was 2,234 years ago which corresponds with 218 BC the exact year Hannibal crossed the Alps.

Professor Chris Allen from Queen’s University in Belfast who discovered the presence of bacteria from horse manure in the soil samples. Source: Channel 4.

At times, the documentary was like an episode of CSI:Miami, especially when Professor Allen explained how he was able to detect high levels of Clostridium bacteria in the sample 40-50 cms beneath the surface. This type of bacteria is normally only found in manure from horses and Professor Allen explained that the high levels of bacteria points to thousands of horses being present on the Col de la Traversette over 2,000 years ago.

Horse similar to that used by Hannibal’s cavalry alongside military historian, Mike Loades. Source: Channel 4.

It is recorded that Hannibal’s army had 9,000 horses with them on their trek across the Alps. The horses were smaller than most horses today and were descended from wild horses that lived in Numidia (modern day Libya). Military historian Mike Loades explained how the Carthaginian horses did not have a saddle or even a bridle but instead, were controlled by a simple hoop around their neck.

Elephants at the Parque de la Naturaleza de Cabarceno in Spain. Source: Channel 4.

Of course, the real reason that Hannibal’s crossing is so famous is because of the 37 elephants he took with him across the Alps. The documentary team visited a nature reserve in Spain to get an idea how easy it is to control a group of elephants. It turns out it is relatively easy to get elephants to do what you want provided they have plenty to eat. Elephants are very martriachal and normally follow their leader, which often is a male but sometimes a female as was the case at the Parque de Cabarceno. So no doubt Hannibal would have put the alpha elephant at the head of his army and then all the other elephants would then follow him or her.

Asian elephants in the Himalayas. Source: Channel 4.

The discussion then moved to how elephants would have coped with mountain terrain. We were treated to another CSI exhibit as an elephant foot was dissected. It turns out an elephant foot is like a mini shock absorber which gives excellent grip in rocky mountain terrain. Footage was then shown of Asian elephants foraging in the Himalayas so no doubt Hannibal’s elephants would have coped with the Alps just fine too.

Sir Richard Jolly who accompanied Jumbo the elephant across the Alps in 1959. Source: Channel 4.

The documentary also included footage from John Hoyte’s expedition across the Alps in 1959. I wrote extensively about Hoyte’s expedition last year but had no idea that there was film footage from their trek. Sir Richard Jolly was 2nd in command to John Hoyte during that expedition and he was interviewed about Jumbo. But at no stage did the documentary or Sir Richard Jolly mention that they had climbed a totally different pass with Jumbo i.e. Mont Cenis, about 100 km north of the Col de la Traversette.

Dr Eve MacDonald and Dr Tori Herridge on the Col de la Traversette. Source: Channel 4.

The documentary finishes with historian Dr. Eve McDonald and paIeo-biologist Dr. Tori Herridge attempting to climb the Traversette pass with a group of donkeys loaded with fodder. I get the feeling the program’s producers would have loved to have finished their documentary with a group of elephants to see if they were able to cross the Traversette but perhaps worried about protests from animal right’s groups, had to make do with some donkeys instead.

Professor Mahaney using string to represent some of the routes Hannibal may have took to cross the Alps. Source: Channel 4.

Overall, I was very impressed with the documentary and my favorite scene from the program is shown above. Why bother with fancy graphics and HD maps when you can simply use different colors of string to get your point across. Professor Mahaney used the string to illustrate some of the different routes that historians think Hannibal may have used to cross the Alps. Even when historians agree about the pass Hannibal used , they can still dis-agree about the route he took to that pass. In the scene above, the white string represents the Traversette route while the red string is the Montgenevre route via the Durance valley and the blue string is the Montgenevre route via the Col du Lautaret. Not shown with string are the 3 other major contenders for the pass used by Hannibal, namely the Col du Clapier, Mont Cenis and the Col du Petit Saint Bernard, which are all located much further north than either the Traversette or Montgenevre.

Professor Mahaney and his team examine a core sample on the Italian side of the Col de la Traversette. Source: Channel 4.

For anyone with just a casual interest in history, the documentary gave an excellent insight into the controversy surrounding Hannibal’s route through the Alps and the ground-breaking work of Professor Mahaney and his team in trying to determine historical events by using CSI style analysis of soil samples. But, having read most of Professor Mahaney’s research papers last year, I was slightly disappointed that there was little in the program that I didn’t already know. However, I was excited to learn that Mahaney and his team were carrying out further tests on more soil samples this time on the Italian side of the Col de la Traversette. The previous samples were all from the French side from an area called the French mire. But we know from both Livy and Polybius that Hannibal set up camp on the Italian side of the summit. Hopefully, the results of the Italian core samples will be published soon to see if there is any similar evidence showing the presence of thousands of horses on the Italian side of the Traversette from 2,200 years ago.

Narrow gorge where Hannibal may have been ambushed. Source: Channel 4.

While my overall impression of the documentary was very good, I was slightly disappointed with some aspects of the program. For example, filming took place in a narrow gorge but the gorge’s location was not given in the documentary. It certainly was an ideal spot for an ambush and may have been somewhere on the Guil river but this was not stated. I was also disappointed by some of the graphics particularly with the depiction of the landslide that hindered Hannibal on his descent down to Italy. This is the key reason why Professor Mahaney believes that Hannibal used the Traversette as it is one of the few locations in the Alps where there is a two tier landslide or one landslide on top of another.

Mahaney’s team examining the two tier landslide on the Traversette. Source: Channel 4.

Both Polybius and Livy describe a huge landslide which was “one and a half stades” in length or about 300m long. Polybius writes

But then they reached a place which was so narrow that it was impossible for the elephants or the baggage animals to move forward at all. There had been a landslide some time previously across nearly one and half stades of the mountainside, and this had been made worse by a second and more recent landslip.

Professor Mahaney believes that this landslide is located roughly 3 km from the summit of the Traversette and at an altitude of 2500m. The landslide was so huge that Hannibal’s army was forced to stop and camp for the night. Livy describes what happened next thus

The only way down was across the rock face, so the soldiers were brought in to build foundations for a track. This involved cutting away the rock, so they felled the large trees in the surrounding area, lopped off their branches, and built a huge pile of timber. They then set fire to it, getting considerable help from the strong wind, which fanned the flames. They then softened up the red-hot rocks by pouring vinegar (sour wine), into the cracks. They then broke up the heated rocks with crow bars and made the whole slope more manageable by creating a series of gentle S-bends down the hillside. As a result both the baggage animals and the elephants were able to be led down the mountain.

The problem with the landslide on the Traversette is that it there are no trees growing near the landslide location. The tree-line on most Alpine mountains is around 1800m and the landslide location on the Traversette  is 700m above that. At an average slope of 15%, the nearest trees would be 5 km away. Hannibal’s army would have needed hundreds of trees to burn a path through such a large amount of rock and having to transport them from 5 km away would have been near impossible. Also Hannibal’s first night in Italy was at a camp near the summit and his second night was at this landslide. It beggars belief that his army only marched 2 km or so from their summit camp before then having to set up another camp due to this landslide.

View of the setting sun from the Col de la Traversette. Source: Channel 4.

Last year I wrote about how scientists were able to date the age of the churned-up layer in the French mire by using carbon dating. However, one of the dates gave an age of 2,070 years before present which is about 200 years after Hannibal crossed the Alps. If the churned up layer was caused by his army, you would only expect to find dates from before 218 BC in the churned up layer. In my opinion, this is a fatal flaw in Professor Mahaney’s conclusion that the churned-up layer was caused by Hannibal’s army. After watching the documentary, it is now also obvious that the location of the landslide on the Col de la Traversette is another fatal flaw. Professor Mahaney’s argument that the tree-line in Roman times was higher than present day does not hold water as the climate in the Alps 2,200 years ago was similar to today.

Monte Viso Tunnel on the Col de la Traversette. Source: Envie de Queryas.com

I was also disappointed that the documentary did not show the Monte Viso tunnel, which is the most famous landmark on the Col de la Traversette. Making a documentary about the Traversette and not mentioning the Pertuis de Viso as the tunnel is called in France is a bit like making a travel show about Pisa and not filming the Tower of Pisa. The tunnel is 75m long and connects France to Italy beneath the summit of the Traversette. It was dug in 1480 and is regarded as one of the oldest and highest tunnels anywhere in Europe. The reason the tunnel was dug was to make life easier for the thousands of donkeys and mules who transported salt up the Col de la Traversette from France to Italy in medieval times. That is why the tunnel is less than 5 ft tall in places because it was designed for donkeys and mules and not for humans who have to stoop down in places to make their way through the tunnel.

Map showing the feudal states in northern Italy during medieval times. Source: Wikipedia.

The Col de la Traversette is located between France and the small feudal state of Saluzzo, which corresponds to modern day Piedmont.. The tunnel took 3 years to dig and was paid for by the Marquis of Saluzzo. At that time, Saluzzo was only a small Italian feudal state and was surrounded by the much bigger Duchy of Savoy which charged a considerable tax on shipments of salt. You can see from the map above the Saluzzo was landlocked and not able to import salt from France by sea without it going through Savoy. So to avoid paying the tax, thousands of mules and donkeys would transport sacks of salts up the Col de la Traversette and into Saluzzo. Some years as many as 20,000 sacks of salt were transported annually. That is an average of 200 sack-loads a day for 100 days in the summer when the pass would be free from snow. A documentary about the transport of salt up the Col de la Traversette in medieval times would make for a fascinating documentary in it’s own right but the subject wasn’t even mentioned once during the Hannibal documentary.

Analysis of core samples from the Col de La Traversette. Source: Channel 4.

It is estimated that at least 1 million sack-loads of salt were transported over the Col de la Traversette between 1000 – 1600 AD. That means there were at least 1 million journeys made by donkeys and mules over this 600 year time period. Many of these mules and donkeys would have stopped to drink at the lake near the summit where Bill Mahaney and his team extracted 2 cores from the sediment. So you would expect these cores would also have a mule fecal deposition layer from around a 1,000 years ago as well as a horse fecal deposition layer from 2,200 years ago. However, there is no evidence of 2 separate layers from the core samples published by Professor Bill Mahaney. In fact, the opposite is the case. There is no evidence of any Clostridim bacteria in the core samples between 30-35 cm in depth which corresponds with 1,000 years ago. In other words, there is no evidence that 1 million mules and donkeys passed over the Traversette between 500 and 1,000 years ago but there is apparently evidence that 5,000 horses and 5,000 mules in Hannibal’s army passed over the same pass 2,000 years ago. This makes no sense. The only explanation for this discrepancy is that the churned up layer was caused by a million mules and donkeys laden down with heavy bags of salt sinking in the soft ground as they drank from the French mire and thereby churning up soil samples from 2,000 – 3,000 years ago. So, in my opinion, the Clostridium bacteria detected by Professor Allen and his team is actually from medieval mules and donkeys transporting salt and not from Hannibal’s army or any other army in Roman times 2,000 years ago.

Route Hannibal may have used to cross the Col de la Traversette. Source: Wikipedia.fr

Not only are there considerable doubts about the landslide location and soil sample analysis on the Col de la Traversette, but there are also considerable doubts about the route Hannibal may have used to reach the Col de la Traversette. Professor Mahaney is a proponent of the British historian Gavin de Beer proposed route for Hannibal shown in the map above. Both Polybius and Livy, 2 historians who documented Hannibal’s life, wrote that Hannibal was ambushed on his first day in the Alps by a Gallic tribe that watched over a pass during the day but who returned to their oppidium or fort at night. Gavin de Beer proposed that the first day ambush took place at the Col de Grimone in the Drome region of France. However, the nearest Iron Age oppidium that has been discovered by archaeologists is at La Bathie Montsaleon which is 30 km from the Col de Grimone. It is very unlikely that Gallic soldiers traveled 60 km a day from La Bathie Montsaleon to the Col de Grimobe and back each day. Hannibal was also ambushed on his 8th/9th day in the Alps. Gavin de Beer has proposed that this ambush took place on the Guil river, possibly at the Chateau de Queyras. But Polybius writes that Hannibal after sheltering overnight at a huge white rock during the ambush reached the summit the following evening. It is roughly 50 km from the Chateau de Queyras to the summit of the Col de la Traversette which is too far for an army to cover in one day.

View looking towards Italy from the Col de la Traversette. Source: Channel 4.

The only redeeming feature of the Traversette is the view of the “plains of the Po” from the summit which is just mind-blowing. But to win the lottery, having one or two numbers is no good, you need all 6 numbers. Likewise, to determine the route Hannibal used you need to identify at least 6 locations including

1) a narrow gorge where Hannibal was ambushed on his first day in the Alps by a tribe that returned to their fort each evening

2) a huge white rock where he was also ambushed on his eighth day in the Alps

3) a location at the summit where his army camped for 2 nights (9th and 10th day)

4) a headland offering “an immense view of the plains of the Po” where Hannibal gave his famous speech (11th day)

5) a landslide location surrounded by trees which Hannibal’s army used to burn a path through the rocks (12th to 15th day)

6) a route that started in territory controlled by a friendly tribe of French Gauls called the Allobrogues and finished in a location controlled by a friendly tribe of Italian Gauls called the Insubres.

In my opinion, the Traversette route only fully meets criteria 4 and partly 2 and 3.  Indeed, many of the claims of Professor Mahaney and others who have championed the Traversette route simply do not stand up to scrutiny. Why try and cross the Traversette when there were much easier passes nearby such as the Col de Agnel. Also if Hannibal made his way along the Drome valley and then the Durance valley, why not keep going until you reach Montgenevre, which is the easiest pass to climb in the whole French Alps. This was the route depicted by Professor Mahaney using red string in the screenshot I highlighted earlier. Unlike the Traversette or Mont Cenis or the Col du Clapier that I looked at last year, Montgenevre was also used by the Romans and is regarded by some historians as the pass used by Hannibal. It was also one of 3 passes climbed by the Wood’s brothers during their Hannibal documentary for the BBC. So I have decided to write a separate blog post looking at Montgenevre in more detail and it can be accessed here in this updated 6 part series looking at routes Hannibal may have used. And in Article 6, I return to the Petit Saint Bernard, which I wrote about 18 months ago and then re-visited during the summer of 2017 to gather even more evidence that this was actually the pass Hannibal used to cross the Alps.

Possible routes Hannibal may have used to cross over the Alps in 218 BC. Source: Author, Datawrapper

Update: August 2020. This article is just one of a total of eight articles I have wrote so far examining the mountain passes Hannibal may have used to cross over the Alps.

Article 1 (published 2017) – Col de la Traversette

Article 2 (published 2017) – Col du Clapier or the nearby Mont Cenis

Article 3 (published 2017) – Col du Petit Saint Bernard

Article 4 (published 2018) – Col de la Traversette (updated) – includes a review of the Channel 4 documentary Hannibal’s Elephant Army : The New Evidence.

Article 5 (published 2018) – Col du Montgenevre

Article 6 (published 2018) – Col du Petit Saint Bernard (updated) – added extra evidence and also some photos taken during a road-trip in August 2017.

Article 7 (published 2020) – Col de Couz – where French archeologist Aime Bocquet believed Hannibal was ambushed on his first day in the Alps.

Article 8 (published 2020) – Col du Chat – where American historian Theodore Dodge believed Hannibal was ambushed on his first day in the Alps.