It's a proven exaggeration by some ancient authors, some of them even greeks. Completely against any archeological, genetic, ethnolinguistic proves. The only who faced a severe reduction of their presence and a PARTIAL emigration were the Senones and the Boii, who were the most anti-roman and authors of some betrayals against the peace treaties with Rome (the Senones even sacked Rome and the Boii invited Hannibal in Italy). The Senones lost the costal plain after the conquest and were completely demilitarized and survived in the Appennines. Anyway, they mixed again in the successive generations with the Picene-Roman coast population, and the regions of Flaminia/Romandiola and Ager Gallicus remained influenced by the cisalpine koiné until NOWADAYS. The other confederation, the Boii (from nowadays Bavaria and Bohemia, Czechia) were, in fact, a collective of c.a. 120 different tribes. Polibius is the main source for the emigration ed expulsion of the Boii from the Po Valley. Anyway, a deeper analysis of the historical sources clearly shows that during and just after the Hannibalic tragedy, the Boii confederation appeared to break up into many different "districts", with different approaches with the Romans. The eastern districts, around Bologna - which appear to still use the name "Boii", fought till the end and faced some violent eradication of minor cities and villages. The towen surrended and than was partially re-colonized by Italic-Roman colonist, but there isn't trace of a destruction or an ethnic cleansing. The western districts, around Modena, Parma and Brixellum appeared to have a different, opposite behavior than Bologna even during the hannibalic war, and the name "Boii" seems to be ceased in use by such districts. We see abitative continuity in many places, we see a celtic-like cult of Minerva in the lower Appennine hills of such districts, and some places mantained celtic names. We have also to say that the celtic tribes were also part of a koiné with a numerically strong (celticized) etruscan and ligurian population. If Modena, Brixellum, Rubiera, Parma, were allied communities, it's very unlikely that the romans expelled people from such places in the aftermath of the war. What it's sure is that the name Boii ceased in use, and probably because of a form of damnatio memoriae for their role in the hannibalic invasion, and that - differently from the Insubres, Cenomanes and others people (Taurini from Piedmont, Anamari from western Emilia and southern Lombardy, etc.) did not maintain their own institution. Probably, after an inter-celtic civil war, the part who was philo-roman identified more into the birth of the cisalpine-roman """nationality""" losing faster than others their late La Tene culture (already partially abandoned for "etruschization"). The so called "expulsion of the Celts" was an archeologically almost invisible phenomenon: probably it regarded some handful of very anti-roman chieftains and their strict armed followers, together with family and servants. They may had enforced the migrating communities of mercenaries and semi-nomadic military operations in the Balkans, Pannonia or even further, but we are talking about some hundreds/thousands of people. Not an exodus.
"What work assumption should be taken the idea according to which the 112 Boic tribes Catone is talking about should be equated to clans, while in the human groups settled in the various "districts" of the ager Boicus a form of social organization (maybe endowed with an ethnic dimension) of an intermediate scale between that of tribes and that of the ethno-political entity. Among the collective activities where the temporary unity of the latter could express itself (involving a large number of its potential components) are wars and religious rites.
In the classical literature, you can see some further aspects of the social and institutional organization of the Boic ethno-political entity between the late IIIrd and the beginning of the IInd century. Various top figures with roles differently labelled and sometimes quoted by their own names appear implicated in the exercise of power, in times of war or preparation for it, involving the boic ethno-political entity and not its individual fractions. The institution of the “diarchy” has been certified and it’s presumably that the re/reucci were appointed to carry out specific missions. There is also traces of an internal article to the boic "aristocracy" and, perhaps, of age classes with different roles in the war, as well as of assembly institutions, possibly divided between a more "popular" council and a more elite one.
Looking at the plan of purely ethnic phenomena, the profile that we have been able to draw of the boic ethno-political entity between the end of the IIIrd and the beginning of the IInd century seems to correspond to a social organization composed of individuals who, plausibly, could invoke ethnic affiliations of a smaller scale than that to whom the endo-ethnonym “Boii” was to be sent back, affiliations that, again as a job assumption, we could imagine refer to human groups housed in various “districts”. If there really were ethnic groups that, for the parties concerned, were sub-groups of the Boii, it’s impossible to recover their names. On the supposedly ethnic dimension of the conceptualization and mobilization of the Boii as a unitary group by those like Boii who could situationally recognize themselves, some considerations are however possible, at least starting from what we have called "dossier Boiorix". The latter has in the center the case reported by Livio for 194, when the regulus named Boiorix, together with his two brothers, raised against Rome the gens of Boii completely. We have assumed that it was in connection with the events that occurred in the 194 mobilization that Boiorix took on such a name, a name that, in the context to which it was passed, has a good chance of being fully felt as an appellation meaning "King of Boii". Boiorix seems to be assured of the leadership of a large collective that, in the peculiar circumstances of the era, had to have forcefully activated the level of identity expressed by the ethnonym "Boii". We don’t know what attribute criteria implied by the end-defination of which we believe to have identified traces for the beginning of the 2nd century. In this way, we cannot say what extent it had, that is, on the basis of more or less inclusive criteria, the population bounded by the social boundary was large, which, in this case, at the beginning of the II century, opposed the Boii to the non-Boii. On a very speculative plan, it is, however, possible that the era of extraordinary mobilization of 194 coincided with the time when it began to express itself that denial of the boycott, which could perhaps be traced in the light of the events of 193, when Boii intended to continue the clash with Rome may have denied the boycott to the “Modenesi” lined up with the Urbe. It is possible but indestructible is that the templum sanctissimum of the Boii cited by Livio was a physical place (not localizable) that, at least towards the end of the 3rd century, had among its functions that of the symbolic center of the Boic ethno-political entity, which contributed to building, maintaining and strengthening the union of the components of this entity. During the III-2nd centuries, it is theoretically possible that, in the “scale” of identities invoked by Cisalpini who at certain occasions thought and eventually presented as Boii, they had placed not only labels designing subsets of “Boii”, but also a label referring to a higher level group than the one designated by the surname “Boii”, if not more labels indicating more “over-boic” identity levels. Based on the survived written documentation, it is impossible that there could have been ethno-political groups of this or these “over-boic” levels, but not that, in case, “over-boich” identity statements could have been exploited in the political-military sphere, in the relationship with Cisalpini and/or Transalpini. Unfortunately, however, no certain conclusion can be reached in this regard. It is also very problematic to evaluate the specifics of the point of view on the labels “Celtic”, “Galati” and “Galli” of how many are defined as Cisalpini Boii by classical authors and/or how Boii could recognize themselves in pre-Roman Northern Italy. There is at least one line of inquiry that might make you think that, in the late 3rd century, members of the Boic ethno-political entity knew an ethnic based on Galat-, but, for the majority, did not recognize themselves in it. This is, however, a conclusion that is not at all obligatory.
As far as the representation of the Cisalpine Boii within the classical ethnography is concerned, we have found that if the Celts/Galati/Galli have been the subject of fairly extensive ethnographic developments, for the classical authors, the Cisalpina Boii did not represent an autonomous “ethnographic center of interest” compared to the inclusive group (the Celti/Galati/Walli). Although the songs about the Roman-Boic conflicts carry various potentially informative data about the social structure and political organization of the communities that appear in the lyrics under the label “Boii”, we only have brief statements that can be classified as explicit ethnographic notes. Among other things, in various cases, these are attributes of characters assigned to Boii not as specifically Boii, but as members of the larger Celtic/Galatic/Gallic family. It is missing, then, a place in the classical literature where a criterion of exo-attribution of boycott is unmistakably activated. Only in Livio is it possible to assume the presence of a latent criteria that, in practice, defined the Boii as the Cispadian Galli, the irreducible enemies of Rome.
Let’s also synthesize what was said about the famous ethnographic song included by Polibio in his excursion on the Keltoiv/Galavtai lived in the pre-Romanian Cisalpine. We argued that, in this fine example of the complexities inherent in the cognitive dimension of ethnicity, the data exposed by Polibio, regardless of their various origin, are put at the service of a device of inferiorization of Celts/Galatians. It is clear that the historian, compared to the data available to him, forces the picture in a direction he considers primitivist, levelling the entire Cisalpine Celticity on how, in his opinion, it was simpler and archaic. According to what is possible to draw from classical sources in this not contradictory archaeological record, the boic ethno-political entity perceptible in the Cispadana of the end of III - beginning of II century, with its population predominantly scattered, its articulation in "districts" and the absence of a "capital" in the political-military sense, yes Candidate like one or one of the models for the polybian painting. Finally, we argued that the question of the “final fate” of the Cisalpine boycott after the final submission to Rome of northern Italy can be addressed by distinguishing between three different analytical plans. As for the fate of the ethno-political entity in the political-military sphere, the situation seems fairly clear. After 191, as an autonomous political entity, the Boii ceased to exist: they had to undergo very harsh interventions and, politically, face rapid destruction. Moving on to the second floor, regarding the fate of the physical persons already subjected/participated in the sovereignty of the Boic political entity, it can be said that, most likely, the individuals recognized by Rome as Boii were not all or almost removed from the Cispadana with extermination, abduction of prisoners to be sold as slaves or expulsions in mass from Italy: in particular, definitely doubtful is the history of the migration to the area south of the middle Danube with which, according to Strabone, the Boii would have responded to the Roman exile. An unquantifiable, but not ridiculous, number of Cispadani known as Boii should be allowed to live on portions of the ex ager Boicus or nearby areas. It is also allowed to cautiously assume that, in Strabone, there is a trace of ethnic discrimination implemented by the Urbe in Cispadana, to be understood both as a categorical distinction between members of different groups, and as a consequent differentiated treatment. At least on certain occasions, representatives of the public res could have reserved a favorable treatment to those they recognized as Cispadani settled among the Boii, but not the Boii themselves.
