They survived for centuries before eventually succumbing to Roman might, because they adopted a number of Indo-European innovations. This allowed them to persist while other communities of their ancestral culture were conquered and culturally and linguistically extinguished by later waves of peoples much earlier.
The Historical Context Of The Etruscans And Rhaetic Peoples
No one doubts the unanimous Roman historical account that the Etuscans were present in Tuscany before the Romans arrived in Italy in the early Iron Age (according to tradition, Rome was founded in the 8th century CE).
The Romans quickly and forcefully assimilated other Italic, but non-Roman, people, such as the nieghboring Sabines who had preceded them in the area. The Indo-European Italic peoples who started to arrive in Italy sometime after Bronze Age collapse ca. 1200 BCE, probably assimilated other non-Indo-European populations of Italy as well, although this is not well documented historically. The Etruscans, however, resisted Roman assimilation until around the 1st century CE, after more than half of a millenium in which they maintains a linguistically non-Indo-European and culturally distinct society from that of the Romans.
Pliny the Younger in his Natural History (79 CE) provides a key piece of evidence regarding their origins. He wrote that:
adjoining these (the [Alpine] Noricans) are the Raeti and Vindelici. All are divided into a number of states. The Raeti are believed to be people of Tuscan race driven out by the Gauls; their leader was named Raetus.The Etruscans, of course, were predominantly associated with the Tuscan region in Pliny's time, so the "Tuscan race" would have referred to the Etuscans, in contrast to the Italic peoples like the Romans who had migrated to Italy more recently.
Pliny's link of the Alpine Raeti and the Etruscans is confirmed linguistically by Helmut Rix (ca. 1998), and also archaeologically. Villanovan material culture migrated from the Alpine area to Tuscany around the time of Bronze Age collapse. (N.B. modern Swiss Rhaetic derived from Latin, and Iron Age Swiss Rhaetic languages, are completely different languages that happen to share the same geographically derived name.)
Both the Rhaetic retreat to the mountains and the secondary Etruscan migration to Tuscany were probably driven by the "push" of early proto-Italic and Celtic populations around the time of the Bronze Age collapse. They were a pilot wave arriving ahead of the Indo-European populations that were expanding into Italy ahead of them.
Indeed, one of the likely reasons that the Etruscans survived as a distinct culture longer than any other the other non-Indo-European cultures of Southern Europe (except the Basque) is that they adopted culturally many of the innovations of the Indo-European Urnfield culture at their heels, and thus could compete with it. If historical accounts and written examples of the Etruscan language had not survived, archaeologists would probably have assumed based upon cultural signs like the practice of cremating the dead that the Etruscans shared with contemporaneous Indo-Europeans that they were just a somewhat distinctive and now extinct variety of Indo-Europeans.
The theory of Herodotus that the Etruscans had Bronze Age origins in Western Anatolian was rejected by his contemporary Greek Historian Dionysius of Halicarnassus for a variety of solid linguistic and religious culture grounds even at the time it was offered. A Bronze Age migration from Western Anatolian also suffers from the fact that Western Anatolia would have been a linguistically Indo-European area (not consistent with the non-Indo-European Etruscan language) for most of the Bronze Age. Genetic evidence, including the latest mtDNA evidence discussed below, also disfavors the hypothesis offered by Herodotus.
The DNA Evidence
The new mtDNA study confirms once again that the Etruscans were surely not derived substantially from Upper Paleolithic indigeneous hunter-gatherer populations of Europe, whose mtDNA was dominated by mtDNA haplogroup U4 and U5.
The new mtDNA study puts common origins between the Etruscans and Western Anatolian populations no earlier than the early Neolithic era.
The ancient DNA evidence also suggest that Etruscans were intrusive to Italy, probably in the archaeologically supported early Iron Age period when Etruscan culture appears in Tuscany. As an earlier ancient DNA study of Etruscans indicates:
Genetic distances and sequence comparisons show closer evolutionary relationships with the eastern Mediterranean shores for the Etruscans than for modern Italian populations. All mitochondrial lineages observed among the Etruscans appear typically European or West Asian, but only a few haplotypes were found to have an exact match in a modern mitochondrial database, raising new questions about the Etruscans’ fate after their assimilation into the Roman state.If the Etuscans were truly autochronous in Tuscany and in Italy more generally, one would expect Etuscan mtDNA haplogroups to be present at low levels throughout Italy. But, this is not the case.
Areas of historical Etruscan occupation also have a relatively high concentration of y-haplogroup G, which is characteristic of first wave Neolithic populations.
The Etruscans Were A Relict Cardium Pottery Migration Wave Population
Etuscans are thus derived from people who arrived as part of a folk migration in the first wave Southern European Neolithic Cardium Pottery culture that included Southern France, Sardinia and all of the territory attributed to the hypothetical Tyrsenian language family to which the Etruscan and Rhaetic languages belong. By the time that their society was documented by Roman historians they had already become a relict population of that culture.
The Lemnian language of the Aegean Sea spoken on that island until the 6th century BCE, which was not within the range of the Cardium Pottery culture, is also proposed (convicingly) to be part of that language family. One plausible hypothesis is that it may represent an eastern colony of the Tyrsenian, aka Cardium Pottery Neolitic descended, culture. It might even have been founded in response to the migration pushes that caused the Etruscans to migrate from the Alps to Tuscanny. Archaeological evidence suggests that Tysenian language family speakers may have arrived around the 9th century BCE. The island is also associated with the center of the cult of Hephaestus, the god of metallurgy, whose secret mystery rituals may have been conducted in a non-Greek language. It could be that this cult arrived with the Tyrsenian colonists and that their metalworking trade is what secured their acceptance in this community.
The Cardium Pottery culture, in turn, was derived from Fertile Crescent Neolithic cultures in what is now Syria and Southern Central Anatolia (rather than Western Anatolia as Herodotus had supposed), although both the donor and receiving regions have seen massive demographic upheaval in the intervening 7500 years (a time frame consistent with the mtDNA analysis in the new study).
The Cardium Pottery culture was distinct from but parallel to the Linear Pottery Neolithic peoples (aka LBK) who were a first wave Neolithic people who expanded demically into a territory including the Danube river basin. The ancient DNA of LBK Neolithic peoples show strong genetic similarities to the Cardium Pottery peoples in terms of haplogroup distributions, particularly on the Y-DNA side. But, the LBK people appear to have had geographically distinct origins from the roughly contemporaneous first wave Neolitic Cardium Pottery peoples. The earliest LBK origins were in Southern Hungary and the Ukraine, perhaps in turn with roots in the Vinča and Karanovo cultures (in turn derived from the Starčevo culture of Southeastern Europe).
Both the LBK and Cardium Pottery cultures, which were first wave farming cultures in much of Europe, were derived, in general, from the greater Fertile Crescent Neolithic cultures in Southwest Asia and Anatolia that had emerged prior to 6200 BCE and starting around 8000 BCE.
The Etruscans Relationship To Other Distinctive Modern European Populations
Of course, all modern populations contain some contributions from later folk migrations and many Cardium Pottery populatioons would have integrated earlier indigeneous Paleolithic Europeans present in the places they migrated to were incorporated to some extent in the Cardium Pottery communities when they arrived.
There is no place in Europe were zero or near zero gene flow between populations is very plausible as a hypothesis other than possibly in the Basques, where RH blood types created a natural genetic barrier to admixture. But, some populations do show fairly strong traces of the early eras of European prehistory in their genes or culture, relative to the majority of Europeans. The main examples are discussed below.
In addition to the (now-extinct) Etuscan and Rhaetic populations of modern Europe (the Rhaetic language died in the 3rd century CE), another population with significant Cardium Ware ancestry that wasn't modified much later on probably include the Sardinians who show great genetic continuity even today with early Neolithic ancient DNA.
The Galicians of Northwest Spain
The Galician people of Northwest Spain in Europe also show signs of being particularly genetically ancient, with disproportionate shares of DNA haplogroups which pre-date the Bell Beaker folk migration (e.g. relatively low levels of Y-DNA haplogroup R1b and some of the lowest low levels of lactose tolerance for the region). The absence of lactose persistance (LP) characteristic of the Galician people is common to both Upper Paleolithic and first wave Neolithic ancient DNA. The Cardium Pottery culture never reached Northwest Spain (in Iberia they were pretty much limited to the eastern coastal areas) and it also isn't clear how fully the population ancestral to them was assimilated into the Bell Beaker culture. My guess would be that their antecedents are really pre-Bell Beaker megalithic peoples who adopted farming from cultures derived from the Cardium Pottery culture later on with greater degrees of incorporation of pre-Neolithic populations than in many other places where farming arrived via folk migrations. Their assimilation to Indo-European Celtic culture was also on the late side within Europe although they were eventually thoroughly assimilated into the Celtic culture and are now Indo-European lingusitically.
The Basque Peoples
In contrast, the Basque have a cultural and genetic distinctiveness that probably has roots in a second wave of folk migration by Bell Beaker peoples in the Copper and early Bronze Ages (tracing just where to the East the Bell Beaker migrants had their origins is a not yet completed puzzle). The Bell Beaker peoples expanding into France from what are now non-Basque parts of Iberia (where the Bell Beaker culture first appears in Europe). In France, the Artenacian culture evolved from and was in continuity with the Bell Beaker culture and held off Indo-European penetration into Western Europe for about a thousand years. The Basque and Aquitani cultures in turn derived from southern migration of members of the Arrtenacian culture.
The Basque seen as having their cultural origins and ethnogenesis in a Copper Age folk migration to Iberia, and from there elsewhere in Western and Northern Europe, persisted when other pre-Copper Age first wave Neolithic and Paleolithic cultures of Europe (many of whom they wiped out) do not, because their technology is on a part with the new Indo-European wave, rather than being clearly inferior. In my view, Bell Beaker derived cultures and migrations fairly described as Vasconic in character, account for the predominance of Y-DNA R1b in Europe, and the distribution of R1b in Europe today roughly corresponds with the distribution of the Bell Beaker culture at its peak. The substrate culture of most of Western and Northern Europe when the transition to Indo-European languages took place in those regions would have almost entirely been part of a Vasconic language family.
The Uralic Peoples Such As Finnish Speaking Finns
The linguistically Uralic peoples of Europe such as the Finnish speaking Finns (other than the Hungarians who acquired their language via language shift from a demically thin elite in the historic era), meanwhile, probably trace their cultural origins to the late Upper Paleolithic indigeneous hunter-gatherer populations of Northern Eurasia associated with the archaeolgical Pitted Ware culture. They were able to persist in their language mostly because their far Northern environment was the least favorable in Europe to the food production methods that the Indo-Europeans and prior waves of Neolithic expansion relied upon for economic dominance.