Hannibal's route across the Alps


article by Jona Lendering

Hannibal's route across the Alps is one of those historical questions that cause endless debate even though the subject has no importance whatsoever. But this does not prevent us from adding some extra speculations.

There are two ancient texts that give a description of Hannibal's route. The oldest is in the third book of the World history by the Greek historian Polybius of Megalopolis (ca.200-118 BCE); at first sight, this text seems to describe a rather northerly route, because it mentions a Celtic tribe, the Allobroges, which lived on the banks of the river Isère in the second century BCE. The other source is the twenty-first book of the History of Rome from its foundation, written by Polybius' Roman colleague Titus Livius of Padua, to English readers better known as Livy (59 BCE-17 CE). He suggests a more southerly route. Both texts can be found here.

Livy and Polybius indirectly used the same eyewitness account. This may have been written by one of Hannibal's companions, Sosylus of Lacedaemon, who wrote a history of the Second Punic War in seven books. Probably Polybius used the original text; Livy knew it indirectly. His real source cannot be identified, but we can be confident that this anonymous intermediary was a careful author, who copied all the chronological indications he found in the eyewitness report. Livy's chronology is therefore precise: 

  Day 1  March to the foothills; first encounters
    Night  Camp on fairly level ground
  Day 2  Moves towards blocked pass
    Night  Attack on abandoned blockade
 Day 3  Enemy attack on baggage train; capture of fortified enemy town 
    Night  Camp in enemy town
  Day 4 Easy march towards the main pass
    Night  Not mentioned
  Day 5  Easy march towards the main pass
    Night  Not mentioned
  Day 6  Easy march towards the main pass
    Night  Not mentioned
  Day 7  Envoys from mountain tribe; their ambush
    Night  Hannibal's infantry separated from cavalry and baggage train
  Day 8  Hannibal's army reunited; continued march towards the main pass
    Night  Not mentioned
  Day 9  Hannibal's army reaches the main pass
    Night  On the summit
  Day 10  Halt on the summit
    Night  On the summit
  Day 11  Halt on the summit; it begins to snow
    Night  On the summit
  Day 12  Precipitous, narrow, and slippery descent; landslide
    Night  Camp on the ridge
  Day 13  Building a road
    Night  Camp below the snow-line
  Day 14  Building a road for the elephants; infantry descends
    Night  At least two camps below the snow-line
  Day 15  Building a road for the elephants; infantry descends
    Night  At least two camps below the snow-line
  Day 16  Infantry reaches plain; first of three days' rest to recover from fatigue

 

 

 

But although Livy's chronology is very detailed, there are certain obscure aspects in his narrative. Polybius understands the military situation better; for example, he explains at the beginning of his story why the Celtic tribes had not attacked Hannibal before he started his crossing of the Alps. Besides, Polybius writes that 

I have questioned men who were actually present on these occasions about the circumstances, have personally explored the country, and have crossed the Alps myself to obtain first-hand information and evidence (World history, 3.48.2).
It is therefore tempting to regard Polybius as more reliable than Livy: he has first-hand knowledge of the Alps, has read the original eyewitness account and understands army maneuvers. On the other hand, Livy has his qualities too, because he carefully copies what has been carefully copied. As a consequence, we cannot choose either of these historical texts as 'most reliable'.

Another approach of the problem is to look at the passes in the Alps, and to find out which one suits the texts best. From north to south, these passes are:

  1. Col du Petit Saint Bernard; this route has been advocated by Barthold Niebuhr, Theodor Mommsen, Lehmann, Viedebrandt, H. Kiepert and Francis de Conninck
  2. Mont Cenis; advocated by Napoleon Bonaparte and H. Nissen
  3. Col du Clapier; advocated by Perrin, Azan, Collins and Wilkinson
  4. Col du Mont Genèvre; advocated by Neumann, Fuchs, Gaetano de Sanctis and Peter Connolly
  5. Col de la Croix
  6. Col de la Traversette: advocated by Sir Gavin de Beer and A. Guilleaume
One of these passes has to suit the following pieces of information, on which Polybius and Livy agree:
  1. The pass has to offer sufficient room to build a camp for at least 20,000 soldiers, 6,000 knights and thirty seven elephants (the number of men that would reach Italy);
  2. The defile should begin within 15 to 30 kilometers from the summit, because Hannibal's soldiers started to climb down on the day they left the camp on the summit.
  3. The road to Italy must be in a northerly direction: the soldiers encountered snows of the previous year when they were descending.
  4. The first part of the descent has to be narrow and steep.
  5. After this, the descent has to be less steep for about 50 kilometers, because it took Hannibal's men three days to reach the plain.
  6. Italy should be visible from the summit (according to Polybius) or from a point at the beginning of the precipitous descent (according to Livy), because Hannibal was able to show his men the plain during a speech.

Condition #6 is the least important, because Hannibal's speech was probably invented. This was a very common practice in ancient historiography: the reader expected short speeches in which the actors explained what they were doing and why. These explanatory speeches were usually included before a particularly important action took place. Since Polybius and Livy both liken the Alps to the walls of Rome, it is likely that the speech was already included in the original account. (Besides, the question seems inevitable how Hannibal's men could possibly see Italy if it were snowing, as Livy indicates.) As we can see in the table below, only one pass fits the sixth condition.

   
1
2
3
4
5
6
Col du Petit Saint Bernard
 2,188 meters
+
-
+
+
-
-
Mont Cenis
 2,084 meters
+
+
-
-
-
-
Col du Clapier
 2,482 meters
+
+
-
-
-
-
Col du Mont Genèvre
 1,860 meters
+
+
+
+
+
-
Col de la Croix
 2,309 meters
-
+
-
+
-
-
Col de la Traversette
 2,950 meters
-
-
-
+
-
+

NB: the ancient snow-line was at 2,000 meters.

The only pass that fits all of the five main conditions is the lowest, the Col du Mont Genèvre between Briançon in France and Susa in Italy. There is an extra argument why this pass is the route taken by Hannibal: the distances best suit the distances mentioned by Polybius (252 kilometers from the Rhône to the beginning of the ascent, and from there to the plain of the Po 216 kilometers). The picture shows the ascent to the Col du Mont Genèvre, some kilometers beyond Briançon as it looked in May 1993.

Now that we know that Hannibal crossed the Alps between Briançon and Susa, we can try to find the other stations of his march. The enemy town that was taken on the third day, can easily be identified with modern Gap, because it is a three days' march downstream from Briançon (i.e., days four, five and six). It is more difficult to establish the route during the first days. Livy states that Hannibal started his march on the banks of a river called Druentia; this cannot be the Durance, because it is too southerly. The Drôme and Isère are possible, and the first one should be preferred because in that case the distance to Gap can be covered in two or three days. The pass which Hannibal took during the second night, can be identified with the Col de Calire.

(The argument that Hannibal encountered the Allobroges and consequently must have passed along the Isère is very weak, because Celtic tribes were not very sedentary. The fact that the Allobroges lived on the banks of the Isère in the second century BCE does not prove that this was their home in the third century.)

Probably, Hannibal had always wanted to take the road to the Col du Mont Genèvre. In those days, it was a common road and the tribes along it knew the mores of international diplomacy (Polybius mentions how the tribe near the pass came to Hannibal with branches and wreaths, the usual symbols of submission.) However, he had already encountered a Roman army near the Rhône; making a detour along the Drôme and the Col de Calire, and catching the main road again near Gap, was a diversionary tactic to give the Romans the impression that they had been able to divert him from the road to Italy.
 
  Day 1 March to the foothills; first encounters, near Die
    Night Camp on fairly level ground; near Die
  Day 2 March towards blocked Col de Calire
    Night Attack on abandoned blockade at Col de Calire
  Day 3 Enemy attack on baggage train; capture of Gap
    Night Camp in Gap
  Day 4 Easy march towards Durance and Col du Mont Genèvre
    Night Camp near Prunières?
  Day 5 Easy march along the Durance towards Col du Mont Genèvre
    Night Camp near Embrun?
  Day 6 Easy march along the Durance towards Col du Mont Genèvre
    Night Camp near Mont Dauphin?
  Day 7 Envoys from tribe near Briançon; ambush 10 kilometers before Briançon
    Night Hannibal's infantry separated from cavalry and baggage train
  Day 8 Hannibal's army united near Briançon; march towards Col du Mont Genèvre 
    Night Camp at La Vachette, near the sources of the Durance?
  Day 9 Hannibal's army reaches the Col du Mont Genèvre 
    Night On the summit of Col du Mont Genèvre
  Day 10 Halt on the summit of Col du Mont Genèvre
    Night On the summit of Col du Mont Genèvre
  Day 11 Halt on the summit of Col du Mont Genèvre; it begins to snow
    Night On the summit of Col du Mont Genèvre
  Day 12 Precipitous and dangerous descent for about nine kilometers (1854 to 1354 meters)
    Night Camp before Cesana Torinese
  Day 13 Repairing the road; infantry starts to descend
    Night Elephant camp before Cesana; infantry camp near Mollières
  Day 14 Building a road for the elephants; infantry descends
    Night Elephant camp before Cesana; infantry camp near Oulx
  Day 15 Building a road for the elephants; infantry descends to Susa
    Night Elephant camp before Cesana; infantry camp near Susa
  Day 16 Infantry stays at Susa; first of three days' rest to recover from the fatigue

Literature

The arguments in this article were brought forward for the first time by Peter Connolly in his book Hannibal and the enemies of Rome (1978 London).


From: http://www.livius.org/ha-hd/hannibal/alps.html (with permission). For another detailed view (in French): http://perso.wanadoo.fr/edouard.begou/alpes.htm

Visit the route!: http://www.andiamoadventours.com/aa_hannibal.html

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