‘In Gaul there are factions not only in all the states, and in all the cantons and their divisions, but almost in each family, and of these factions those are the leaders who are considered according to their judgment to possess the greatest influence, upon whose will and determination the management of all affairs and measures depends. And that seems to have been instituted in ancient times with this view, that no one of the common people should be in want of support against one more powerful; for none [of those leaders] suffers his party to be oppressed and defrauded, and if he do otherwise, he has no influence among his party. This same policy exists throughout the whole of Gaul; for all the states are divided into two factions.’

[Caesar, The Gallic War, VI. 11]

When we try to understand the form of Vercingetorix’s army, we are faced with a number of problems. Documentary records provide some descriptions, but not even Caesar describes Vercingetorix’s army in detail. On the whole, the information sources for Gallic society and warfare are problematic: they mainly come from ancient authors who rarely provide us with the type of perspective we require to place the Gauls correctly in context. Often the sources themselves are not first-hand, being repetitions of other authors or uncritical retellings of travellers’ stories. However, Caesar’s Gallic War, along with other ancient sources, provides us with some useful descriptions of the Gallic peoples, although we must be wary of accepting his descriptions in too unquestioning a manner.

Caesar had his own reasons for writing his works: they promoted his image and presented Roman actions positively. In addition, Caesar gained much of his information on the battlefield or in the political arena – hardly the place to discover the nuances of a nation’s culture. And so, like other authors before him, he resorted to using previous works to fill in the gaps of his experience. The physical appearance of ‘Celts’ given by Caesar matches authors such as Strabo, Diodorus Siculus, and Pliny. These all focus on the remarkable aspects of the Celtic appearance that were unusual to Mediterranean eyes: fair skin, hair and blue eyes. The descriptions of Gauls are often derived from those peoples closest to Roman provinces and show little of the range and complexity of the Celtic societies further away. By portraying the Gauls as ‘barbarians’, the Romans could focus attention on certain Gallic attributes for their own purposes, sometimes to contrast how well the Romans behaved, sometimes to show how badly. There was a certain contradiction in this, as the Romans sometimes ridiculed behaviour in the Gauls that the Romans themselves engaged in.

‘These [nobles], when there is occasion and any war occurs (which before Caesar’s arrival was for the most part wont to happen every year …), are all engaged in war. And those of them most distinguished by birth and resources have the greatest number of vassals and dependants about them. They acknowledge this sort of influence and power only.’

[Caesar, The Gallic War, VI. 15]

Vercingetorix’s army was based on the ad hoc accumulation of willing participants organized along tribal lines, in contrast to the Roman army’s formal standing armies with strict military structures. One way to understand how Vercingetorix’s army functioned, therefore, is to understand the structure of wider Gallic society. A problem when attempting to reconstruct Vercingetorix’s army in this context is the fact that Gallic society had little homogeneity. At the time of Caesar’s invasion, Gallic culture was still rooted in prehistoric religious and tribal customs, which differed from tribe to tribe. The role of the ‘king’ is a good example. It sometimes commingled the role of leader with that of high priest. In many tribes, however, attempts were made to keep these two roles separate. Religion still played a dominant role in Gallic life and priests took the role of wise arbitrators seriously, attempting to balance military and civilian leadership by halting the unrestrained power of either. By Caesar’s invasion, kingship in some tribes was starting to be replaced by elected positions, much like the process that had happened previously in classical Mediterranean civilizations. The Aedui (whose capital at Bibracte was used as the focal point of the Alesia Campaign) seem to have been one of the most advanced along this process, although many other tribes were also developing similar mechanisms. At the time of the Alesia Campaign the Aedui had developed a constitution and had an elected magistrate called a vergobret, who functioned in the role of king. Separate from this civilian magistracy there was also a growing military magistracy. In charge of these was a military chieftain – a role that separated the military and political functions of the leaders, thus preventing the concentration of power in a single person’s hands. A larger group formed solely from the nobility of the villages formed a ‘senate’ that would decide the grander fate of the tribe as a whole, such as whether it went to war or the election of magistrates. Nobles tended to come from kin groups with a long history of noble or renowned ancestors and marriage between these noble families helped maintain their status. Vercingetorix’s attempt to unify Gaul was therefore seen by some Gauls as an attempt to circumvent the new structures and revive a system of hereditary kings that would place him foremost.

‘the commonality is held almost in the condition of slaves, and dares to undertake nothing of itself and is admitted to no deliberation. The greater part, when they are pressed either by debt, or the large amount of their tributes, or the oppression of the more powerful, give themselves up in vassalage to the nobles, who possess over them the same rights without exception as masters over their slaves.’

[Caesar, The Gallic War, VI. 13]

Although social divisions were clearly demarcated, the struggle for power within these groups was inevitable. Even within noble families, members would compete with each other for support in order to gain supremacy. However, Gallic clientage was where the real social power was held and this was based on how many supporters an individual could accumulate. This system enabled wealthy chieftains to extend their control over large numbers of followers with little regard to social standing, tribal boundaries or definitions. Honour was a major feature of this relationship and this meant commoners had to be protected by their leaders. If they failed, they lost their honour and also their clients. This was a mutually beneficial system whereby wealthy individuals would protect their ‘clients’ and, in return, would be supported by them. Caesar makes note of this system, describing it as an ancient Gallic custom, but it was also very similar to Roman practice. So long as a leader could guarantee support and protection to his clients he would be maintained as leader. These social distinctions exhibited in the political system were apparent in the military system. At Alesia, the tribal leaders used this relationship to gather bands of warriors, calling upon those who owed them allegiance.

The Gallic tribes, like all ‘Celtic’ peoples, had a society based on warrior ideals. War was not only seen as destructive, but also productive. The necessary hierarchies required for military combat reinforced the social ties and structures they were formed from. In order to fight, a Gaul had to have achieved puberty and be wealthy enough to own his own arms. This mechanism guaranteed that each warrior had a stake in the successful outcome of the battle. At the top of the social pyramid was the military chieftain, a post that was annually elected and maintained only a controlling position over the ‘armed council’ that decided matters of warfare. These were made up of the nobility, who held the most prestigious place in battle, due in part to their ability to furnish themselves with both horse and complete panoply of the best quality armour. At the bottom were various levels of commoners who were mainly consigned to the ranks of the infantry, although they were not confined to that status – the possibility was always open to them to improve their position. In times of social upheaval it was not unknown for commoners to be a central part of societal transformation. Commoners retained their rights as freemen, whether they were well off and landed or part of the underclass. On the other hand, slaves were non-citizens with no rights. Often either captured or bought outsiders, their role was servile. Although their position could be changed and their lowly status was not always passed on to their offspring, only in extremis were slaves allowed to fight.

At the outset of hostilities the council called together an assembly of all the warriors, usually at a central place in the tribal region. During the Alesia Campaign, the hill fort at Bibracte was used as the focal centre, not only for the Aedui tribe, but also for the whole of the rebellious tribes of Gaul. With all of the available warriors armed and drawn together, the armed council could assess the state of readiness of the army.

These events could also be an opportunity for intertribal competition through the display of prowess and equipment, showing their readiness and willingness for war. Weapons were not only used for war but also could signify an individual’s status within society. The type of weapon a warrior had and how elaborate or decorated it was influenced how others interacted with him.

‘The nation of all the Gauls is extremely devoted to superstitious rites; and on that account they … who are engaged in battles and dangers, either sacrifice men as victims, or vow that they will sacrifice them, and employ the Druids as the performers of those sacrifices; because they think that unless the life of a man be offered for the life of another man the mind of the immortal gods cannot be rendered propitious, and they have sacrifices of that kind ordained for national purposes.’

[Caesar, The Gallic War, VI. 16]

Before battle it was not uncommon for rites and rituals to be performed and augurs to divine the fate of the battle. The Gauls had a range of gods forming an organized system of belief, depending on tribal preference. Many of the Gallic gods were directly associated with sky gods, the war god being one of the greatest. Usually the war god also had a male and female appearance and these often had positive and negative characteristics, which manifested as constructive or destructive traits. By the Roman invasion of 58BC, the Roman and Gallic gods were very similar in general terms, showing something of their shared Indo-European origins. After the assimilation of Gaul into the Roman Empire, these shared origins led to the relatively easy incorporation of the Gallic gods within the Roman pantheon.

‘Mars presides over wars. To him when they have determined to engage in battle, they commonly vow those things they shall take in war. When they have conquered, they sacrifice whatever captured animals may have survived the conflict, and collect the other things into one place. In many states you may see piles of these things heaped up in their consecrated spots; nor does it often happen that any one, disregarding the sanctity of the case, dares either to secrete in his house things captured, or take away those deposited; and the most severe punishment, with torture, has been established for such a deed.’

[Caesar, The Gallic War, VI. 17]

Particularly common war gods were Teuates, Esus and Taranis; these gods usually had a physical manifestation, particularly on the battlefield.

War gods also tended to be bloodthirsty and some writers suggest that they were only appeased with human sacrifice. Examples of such sacrifices were the drowning of a man in a tub to appease Teuates, hanging a man from a tree and pulling him to pieces to encourage Esus and encasing several people in a hollow tree and burning them to satisfy Taranis. Rites attributed to war gods often focused on the ritual deposition of war booty and sacrifice of captives.

‘According to their natural cruelty, they are impious in the worship of their gods; for malefactors, after that they have been kept close prisoners five years together, they impale upon stakes, in honour to the gods, and then, with many other victims, upon a vast pile of wood, they offer them up as a burnt sacrifice to their deities. In like manner they use their captives also, as sacrifices to the gods. Some of them cut the throats, burn, or otherwise destroy both men and beasts that they have taken in time of war.’

[Diodorus Siculus, Historical Library, II]