The paper is out, Ancient Rome: A genetic crossroads of Europe and the Mediterranean:
Ancient Rome was the capital of an empire of ~70 million inhabitants, but little is known about the genetics of ancient Romans. Here we present 127 genomes from 29 archaeological sites in and around Rome, spanning the past 12,000 years. We observe two major prehistoric ancestry transitions: one with the introduction of farming and another prior to the Iron Age. By the founding of Rome, the genetic composition of the region approximated that of modern Mediterranean populations. During the Imperial period, Rome’s population received net immigration from the Near East, followed by an increase in genetic contributions from Europe. These ancestry shifts mirrored the geopolitical affiliations of Rome and were accompanied by marked interindividual diversity, reflecting gene flow from across the Mediterranean, Europe, and North Africa.
If you don’t have access to the paper, the supplements are very good, with lots of visualizations.
The figure above summarizes the main clear dynamic: the period of cultural and genetic cosmopolitanism of the Imperial period turned out to be ephemeral. The authors express a bit of surprise that the cosmopolitanism of Roman genetics during the Imperial period seems to manifest itself in an ‘eastward’ shift, and hypothesize that this is due to the greater population density of the eastern provinces.
This is almost certainly true.
The western focus of the early Roman Empire was somewhat at odds with the reality that the wealthiest and most populous domains were located in the eastern Mediterranean. The shocks of the 3rd-century resulted in an eastward orientation because that’s where the largest cities and tax base were. The Greek-speaking east, in particular, continued to provide the intelligentsia even throughout the Classical period, and due to the wealth of eastern cities, it is plausible that the mercantile elite of the capital often had eastern roots. The prevalence of Greek inscriptions in burials also is strongly indicative of eastern people in the capital.
That’s all to be expected. But what happened after the fall of Rome? The evidence above shows a western and northern shift. Though the proximal populations that contributed to this shift are somewhat different, overall the distal ancient components (e.g., “Neolithic”) return to frequencies that are closer to Iron Age Latium than the Roman Imperial phase. How did this happen?
Ancient DNA is a great window into the past, but it needs to be synthesized with an understanding of historical and anthropological processes. The Rome of the 400s was still a massive city, only marginally off its imperial peak in terms of population. But the Rome of 600 A.D. was a city filled with emptiness. What happened? A combination of the wars of the 6th-century, which are recorded to have depopulated much of Italy, and the overall decentering of Rome from the Mediterranean system after the ending of the Western Empire, probably resulted in the inevitable contraction of the Eternal City.
Of course, Rome grew again over the centuries. But the new Romans were not the same Romans as those of the Roman Empire, who left few descendants. In addition to far off cosmopolitans, the bulk of the population was probably derived from northern Lazio and southern Tuscany. Rural people whose genetic makeup resembled the Iron Age Italians from whom they descended.
This answers the question that people have been asking for decades: are modern Romans descended from the people of Republican Rome or Greeks and Syrians who transformed themselves into Romans? The answer is neither. Modern Romans descend from Italian peasants, who were less impacted by the predations of the Goths and Byzantines, and had higher fertility than urban dwellers even in peaceful times.
Which brings me to a second paper in the same issue of Science, The Church, intensive kinship, and global psychological variation:
There is substantial variation in psychological attributes across cultures. Schulz et al. examined whether the spread of Catholicism in Europe generated much of this variation (see the Perspective by Gelfand). In particular, they focus on how the Church broke down extended kin-based institutions and encouraged a nuclear family structure. To do this, the authors developed measures of historical Church exposure and kin-based institutions across populations. These measures accounted for individual differences in 20 psychological outcomes collected in prior studies.
The results are not that surprising, though the statistical rigor of the paper is impressive. I first encountered the idea about the instrumental role of the Western Church in imposing a new family order in Western Europe in Adam Bellow’s In Praise of Nepotism (others may have heard about this via HBD Chick). Bellow offers a very simple explanation: the early Roman Catholic Church used its ideological power to prevent the emergence of powerful lineage groups. More concretely, limiting marriage prospects of elite lineages increased the probability that properties of wealthy families would be given to the Church as a gift.
In some ways, this paper has nothing to do with the first. But note that the period when the Western Church began to transform the familial structure of Western Europe is at the end of the Roman Empire. Between the 6th and 9th centuries the Roman Church was a particularly cosmopolitan institution in a rapidly barbarizing Western Europe. In the 7th and early 8th century, there were a series of ethnically Syrian Popes, to give one example. As the post-Roman world in the West began to devolve into localism, the Western Church remained international. Global.
Consider then this Late Roman institution, the Western Church, a locus of urbane cosmopolitanism reflecting the civilian values of the ancient Roman aristocracy, surrounded by a rising tide of unlettered barbarism in the form of marginally Christianized Lombards and their ilk. This cultural tension during these centuries of Late Antiquity may lay at the root of the ideological program promoted by the Western Church against the ascendent barbarian elites which had inherited the mantle of Rome.
Finally, a map within this paper showing the role of kinship in modern societies illustrates a striking pattern:
In Victor Lieberman’s Strange Parallels he asserts that Southeast Asia, like Europe, is part of a “protected zone” against the predations of the steppe. As such, it retained stability and continuity which allowed for the emergence of modern nation-states. Notice that Theravada Southeast Asia has a low kinship index, just like Europe (Vietnam, like China, has a high kinship index probably because of Confucianism’s focus on family as the atomic unit of society). Japan, also part of the “protected zone”, has a low kinship index.
It strikes me that exploring the role of institutions and historical contingency in these regions in decreasing the importance of familialism might be something that needs to be done. With that being said, the fact that the Western Church inherited Greco-Roman aversion to polygamy and innovated its own aversion to consanguinity resulted in a very unique familial configuration in Western Europe. Monogamous. Deemphasizing the extended kinship group.
We live in a time when some people would assert that “Western civilization” is a racist term. But it seems to me that these tendencies within Western civilization are highly correlated with flourishing and innovative societies.