The Gallic War
"Cease ye, therefore, to pity the Clusians when we
besiege them, said Brennus" - Plutarch
Southward expansion
The Celts and the Romans had an extented history of conflict during the Heroic age before Caesar's Bellum Gallium 'Gallic War', and it is well worth considering the dynamic between the Celtic tuatha with the city of Rome during the Republic to provide an historical context to Caesar's expansion of Empire and view their respective attitudes toward land, territory, expansion and war, and also to highlight the wealth of historical records of the Celts in this time.
Celtic tuatha had settled the regions "towards the northern ocean [and] between the Pyrenees and the Alps", the Mediterranean coast west of the Alps, "long before" 390 BC and in this period the Celts had established trade with the Etruscans in Italy, especially enjoying the import of wine, a commodity not able to be produced in the north (Plutarch, Life of Camillus, 15).
Expansion into the Italian peninsula would have appealed due to the productive land there: they moved in response to population increase, "in search of new land, that which they occupied being insufficient for their numbers" (Appian, Gallic History, The Embassies fragment) and settling "in quest of the land which produced such fruit" (Plutarch, Life of Camillus, 15), "envying the beauty of their lands" (Polybius, Histories, 2.17).
The region settled was in the northern part of Italy below the Alps, the valley of the Po river, from the Ligurian Bodincus 'bottomless', called by the Greeks Eridanus and named Padus in Gaulish after the "great numbers of pine-trees, which in the Gallic language are called padi" (Pliny the Elder, The Natural History, 3.20).
Brennus
Celtic expansion into the Etruscan territories made a great impact upon the peoples of the Italian peninsula. The Celts, named as the tuatha of the Ananes and the Boii (Polybius, Histories, 2.17), came into conflict with Rome through Roman alliance with the Etruscans of Clusium and their gross mismanagement of ambassadorial missions with the Gauls (Appian, Gallic History, Embassies fragment). During these missions, Brennus, king of the Gauls noted "being able to till only a small parcel of earth, they [the Clusians] yet are bent on holding a large one" (Plutarch, Life of Camillus, 17), pointing out the surplus of land available for use.
Brennus pointed out to the Romans that his people were expanding in no different a manner than the recent Roman expansion into her own neighbourhood, and added "Cease ye, therefore, to pity the Clusians when we besiege them, that ye may not teach the Gauls to be kind and full of pity towards those who are wronged by the Romans" (Plutarch, Life of Camillus, 17).
As a consequence of Roman treachery during these embassies, under the kingship of their ri Brennus, the Celts attacked the city of Rome, taking all but the Capitoline Hill (the subject of Plutarch's Life of Camillus). During the seige, an event is related by Appian (Gallic History, Peiresc fragment) showing the Celtic respect of religious tradition: They allowed a Roman priest "to make a certain yearly sacrifice in the Temple of Vesta, and passed safely, with sacred utensils, through the ranks of the enemy, who were either awed by his courage or had respect for his piety and his venerable appearance."
Cisalpine Gaul
The Celtic attack on Rome in 390BC had an enduring impact on Rome and was invoked over the centuries that followed. The threat to Roman security that the Celts represented fed the Roman concept of imperium 'authority to rule'. Over the forty years following the sack of Rome, the Celtic tuatha settled in the north of Italy came under the authority of Rome, forming the region of Cisalpine Gaul (Appian, Gallic History, Epitome fragment; Polybius, Histories, 2.14-18).
An uneasy relationship between Celt and Roman over the period from 350 to 225BC included open hostilities. In 283BC, "the Romans sent the first colony which they ever planted in Gaul; namely, the town of Sena [Gallica], so called from the tribe of Gauls which formerly occupied it [the Senones, and] lying on the coast at the extremity of the plains of the Padus" (Polybius, Histories, 2.19). The Celtic response was open war with Rome, in which the Etruscans and Boii were defeated, and after which Rome's attention was directed to the wars with Pyrrhus who they exhausted. Interestingly, it was in this period that the Celtic attack on Delphi was made. Rome then launched war with Carthage for domination of Sicily (264-241BC).
Important to the development of Rome, and future actions against the Celts, Sicily (and likewise Corsica and Sardinia) was not incorporated into the growing Italian confederacy, but ruled as the first provincia of a governing magistrate. In the aftermath of victory, the Cisalpine Gaul region in which Rome held territory was in 232BC distributed amongst the Roman citizens: At last the Celtic attitude toward Rome became forged and the Boii realised "that the object of Rome in her wars with them was no longer supremacy and empire over them, but their total expulsion and destruction" (Polybius, Histories, 2.21).
From the Celtic perspective, the fate of Sicily would be theirs if they did not act: In Sicily, both Carthaginian and Rome's Greek allies in southern Italy had held interests, and Carthage had been expelled. In Cisalpine Gaul, the combination of Roman and Celtic interests was directly at stake, and the Celts realised Rome meant to occupy the region. In the war that followed, from 225BC, Celts from beyond the Alps were also engaged. In Rome, "the old fear of the Gauls had never been eradicated from their minds" and throughout the Italian peninsula generally, "each people regarded it as a danger menacing themselves and their own city and territory" (Polybius, Histories, 2.23).
For three years (Polybius, Histories, 2.19-34) Rome led a general mobilisation of Italy against the Celts to defeat. It was therefore clearly in Celtic interest to support Hannibal in his march from Iberia toward Italy in 218BC (Appian, The Hannibalic War, 1.4).
Celtiberia
The fifteen year long second war against Carthage was fought through an unending series of battles led by Hannibal throughout the Italian peninsula, but not the city of Rome. The tactical manouever of bringing the war away from Italy and across the Mediterranean by Scipio ended the standoff, and a fifty year treaty signed (The Treaty of Zama, 202BC; Appian, Punic Wars, 8.54). Ejected from Iberia, the Carthaginian territories there came into Roman control, organised like Sicily into provincia of governing magistrates, Iberia Ulterior in the south and Iberia Ceterior in the east. Consolidation of these provinces led over the following sixty years to defeat the independent interior.
In this way the Romans came against Celtic peoples in Iberia, for "the Celts, passing over the Pyrenees at some former time, mingled with the natives, and that the name Celtiberia originated in that way" (Appian, The Wars in Spain, 1.1). In Plutarch's Life of Cato the Elder (10) we see Roman practical diplomacy at obtaining allegiance of the Celtiberians in their efforts, where the consul "appealed to a neighbouring tribe, the Celtiberi, to join forces. When they demanded two hundred talents as the price for their assistance...Cato saw nothing shocking in this. If the Romans won, they could pay their allies out of the spoils of the campaigns, not out of public funds, and if they lost there would be nobody left either to ask for the reward or to pay it. In the battle which followed he won an overwhelming victory, and...the number [of cities] taken amounted to four hundred."
That was in 195BC, and only in 133BC was the Celtiberian capital of Numantia destroyed under Scipio Aemilianus, after the humiliation of Roman forces there in 134, when envoys were sent to the Numantines "to propose a truce and arrange terms for a peace" (Plutarch, Life of Tiberius Gracchus, 5).
At their defeat, " their leader, Avarus, discoursed much about the prestige and bravery of the Numantines, and said that even now they had done no wrong, but had fallen into their present misery for the sake of their wives and children, and for the freedom of their country. 'Wherefore, O Scipio,' he said, 'it is worthy of you, as a man renowned for virtue, to spare a brave and honorable race and to extend to us terms dictated by humanity, which we shall be able to bear, now that we have at last experienced a change of fortune.'" (Appian, The Wars in Spain, 15.95).
Scipio razed Numantia to the ground. He was the same Scipio who razed Carthage in 146BC, after the Senate in Rome had decreed in 149BC to remove the Carthaginian threat to Roman imperium, with "orders not to desist from the war until Carthage was razed to the ground" after the conclusion of the Treaty of Zama (Appian, Punic Wars, 11.74).
Brothers and Kinsmen
The formation of two further provincia by Rome, namely Africa after the destruction of Carthage in 146BC, and Macedonia following assertion of imperium with the destruction of Corinth in the same year, was not unfelt by the Celts in Gaul, for the whole Mediterranean world was coming under the control of Rome in the second century BC. In 125BC, Rome began her imperium upon Gaul.
Massalia, near the mouth of the Rhône, had long been an ally of Rome, and it was past this city that Hannibal had passed. Massilia "distinguished itself above all other places, before and since, in fidelity to Rome, and never more so than in the Hannibalian war" (Polybius, Histories, 3.95). In 154BC and again in 125BC Massilia appealed for assistance in repelling raiders in her environs, the Ligurians, and entered the territory of the tuath of the Vocontii, to the north. The movement of Roman troops into this region provoked the tuatha of the Allobroges, allies of the powerful the Arverni, whose territories lay inland to the east and west of the Rhône, and the Allobroges took in the fleeing Ligurian king and other leaders, of whom Rome demanded but the Allobroges refused (Appian, The Gallic History, Embassies fragment).
At this time the Allobroges were in dispute with the tuath of the Aeduans, to their north. As a means to help defeat the Allobroges, the Romans made alliance with the Aeduans having thm declared in the Senate 'Brothers and Kinsmen of the Roman People' (Caesar, Bellum Gallium, 1.33). This title was commonly conferred by " the romans to make foreign friends of any people for whom they wanted to intervene on the score of friendship, withot being obliged to defend them as allies" (Appian, The Gallic History, Embassies fragment). It was an important mechanism put in place by the Romans, for they required under the Republic to only conduct 'just' wars, termed casus belli which was sanctified by the fetiales college of priests to ensure righteousness in action (see, for example ex praecepto librorum facti 'prescription of the Sibylline Books', Livy, Periochae, 49).
The Province
Thus in 122BC, Rome's direct influence in the interior of Gaul had become established. In addition, a presence was established, also in 122BC, north of Masillia near some hot springs, the site of a town, the colony of Aquae Sextiae (Aix), which was their first settlement north of the Alps. With the defeat the following year of the combined forces of the Arverni and the Allobroges under their ri, Bituitus (Appian, The Gallic History, Embassies fragment), the Senate at Rome declared the formation of provincia over the Gallic territories, forming the Province of Transalpine Gaul.
The process begun by the settlement in Cisalpine Gaul a century previously, and through the wars against Carthage and Corinth, had finally reached Gaul. The southern region, bound by the Jura mountains, had become a Roman Province.
The ancient city of Narbo, toward the west along the provincial coast, long a trading place for British tin like Massilia was established as a Roman city in 118BC, firmly embedding provincial rule and giving rise to the name Narbonensis for the Province. Five years later the beginnings of the Germanic intusions into Gaul commenced.
There was great alarm at Rome at three hundred thousand invaders "like a thundercloud...of the German tribes, whose territory extends up the northern ocean [with] the German word for plunderers [,that] is Cimbri" (Plutarch, Life of Gaius Marius, 11). Their defeat, together with the Teutones in 101BC, was achieved by Gaius Marius, who "saved the city, they said, from a danger just as great as had been the invasion of the Gauls" (Plutarch, Life of Gaius Marius, 27). In the proceedings of this war, the kings of the Teutones had made an escape "to the Alps and had been captured by the Sequani" (Plutarch, Life of Gaius Marius, 24) and delivered to Marius, showing the continued collegial attitudes of northern tuatha towards Rome after the establishment of the Province.
Imperium
Over the three hundred years from the movement of tuatha south of the Alps to the incursions of the Germans into Gaul, the Roman Republic had grown from a city-state to a provincial empire. The bordering cultures had endured a stressed relationship heavily influenced by the stand-off with Brennus in 390BC. Rome's development of imperium, the 'authority to rule' was in tension with the Celtic 'right to utilise land' (to distill the concept originally outlined by Brennus (Plutarch, Life of Camillus, 17).
The military development of Rome became highly developed and compared to "the Gauls [who] showed no power of planning or carrying out a campaign, and in everything they did were swayed by impulse rather than by sober calculation" Polybius, Histories, 2.35), and consequently eventual Roman victory in campaigns was consistent. Tuatha of Gaul maintained their political independence, displaying antagonism or alliance toward each other, or toward Rome; and Rome had established Provincial rule in the south, supplemented by 'Brothers and Kinsmen of the Roman People' alliances with tuatha to the north. This, then was the condition of Gaul in the first century BC, the condition in which Julius Caesar was to alter forever.