This article was originally featured on MIT Press.
November 26, 1922, marks what is arguably the most famous discovery in the history of archaeology. On that day, the British Egyptologist Howard Carter made a small hole through which he could insert a candle in the sealed doorway of Tutankhamun’s burial chamber and thus lit the interior. As his eyes slowly adapted to the darkness, he was able to make out a chamber that had not been disturbed for over 3,000 years.
Tutankhamun was just an obscure pharaoh during his lifetime, and there is evidence that he was hastily buried; the second of the three nested coffins seems to have originally belonged to someone else. And yet the inner coffin, in which his mummy was discovered, is made of solid gold, weighing almost 250 pounds. One can barely imagine how impressive the burials of such powerful leaders as Khufu, Thutmose III, or Rameses II must have been; alas, they were all looted in antiquity.
But contrary to popular belief and cinematic glorification, most archaeologists would say that the search for spectacular treasures isn’t their main research objective; they want to understand the daily life of past civilizations. Still, both extremes—the fabulous wealth of kings and the hardscrabble existence of common people—contribute to an understanding of what can be argued is one of the main goals of archaeology: to document and study the evolution of inequality in ancient societies. This also involves the question of how to recognize and quantify it.
One of the most obvious approaches would be through the assessment of differential goods deposited in graves. But richly furnished graves may not simply be evidence of social differentiation; rather, they may be an attempt to demonstrate the importance and distinction of a family in relationship to other kindreds—a social importance that may not exist in reality. Moreover, social stratification can be based on wealth but can also be based on personal prestige and power. Therefore, it isn’t always possible to assess social differences by comparing graves with goods to those without them.
Some archaeologists have attempted to apply economic principles to examine social differences at specific sites and, crucially, compare the data from different places. A study led by Samuel Bowles from the Santa Fe Institute and published in Nature in 2017 tried to address this question by applying the Gini coefficient—a single number most commonly used to measure income inequality—across a large number of sites from the archaeological record, both in the Old World and the Americas. The list of sites included paradigmatic cities such as Çatalhöyük in Turkey, Pompeii in Italy, and Teotihuacan in Mexico; the authors measured the dimensions of houses as estimated indicators of wealth.
Among modern hunter-gatherers, the team found, the Gini coefficient is low—around 17 (on a scale of 0 to 100). This is not surprising as few objects can be carried in nomadic societies, and consequently, personal qualities such as the ability to hunt count for more. This does not mean that some people didn’t have a higher social status; material culture was probably so poor—or so different from our perceptions of status—that it is difficult to grasp social differences among past hunter-gatherers.
In the ancient farming societies under study the Gini coefficients are estimated to have been between 35 and 46; interestingly, the real measurements were lower than those obtained from records. For instance, among the ruins of Babylonia, researchers estimated a coefficient of 40, yet an estimate based on information from the Babylonian chronicles resulted in a higher coefficient of 46. The ancient accounts likely overemphasized the size of the largest houses in admiration. This is not unlike what happens when we return from a trip: We sometimes tend to exaggerate the things that we’ve seen.
Nevertheless, the most remarkable differences come from the comparison of the societies of the Old World and those of the Americas, with the latter being much more equal in the Gini coefficient, despite being highly hierarchical in some cases such as the mighty Aztec Empire. Researchers conclude that the root of these differences could be ecological since there were more and larger animals to be domesticated in Eurasia—such as cows, horses, pigs, sheep, and goats—than in the Americas, with only dogs and turkeys, and this trait alone created a differential system of accumulated wealth.
At the Aztec capital, Tenochtitlán, for instance, houses had highly standardized dimensions and were all quite similar. Aztec society, even with its horrific human sacrifices, was at the time of the Spanish conquest more egalitarian than Mexico 200 years later, when the European elite had created the encomienda system, under which the Indigenous population worked in semislavery. Within a few generations, the concentration of wealth had almost doubled in the colonial New World, with a consequent increase in inequality.
When did these differences between the Old and New Worlds emerge? Early farming societies had the possibility of generating and storing food surpluses, creating potential scenarios for differences in population size along with a certain degree of inter- and intrasettlement inequality. A recent application of the Gini coefficient to 90 sites from the Near East and Europe showed a remarkable increase of inequality thousands of years after the advent of agriculture—a finding that would indicate it was not farming per se that created unequal societies. According to the authors, at some point some farmers were able to maintain specialized plow oxen that could cultivate 10 times more land than other farmers, thereby transforming the economy toward a higher value of land in detriment of human labor.
This emerging inequality at the end of the Neolithic could explain a remarkable example of wealth dating from that period: the Varna burial. This burial was found in a Copper Age cemetery in modern Bulgaria and is dated to 4560–4450 BCE; it contained more gold than the rest of the world possessed at that time. It contained an adult male — likely a chieftain or king of some sort—who was buried holding a gold war mace; curiously he also had a gold penis sheath of unknown meaning. Still, such findings are exceptional, and there is a general consensus that Neolithic societies were more egalitarian than later ones.
Inequality clearly increased with the arrival of metals, which partly allowed, from 3000 to 2000 BCE onward, the appearance and development of a social organization based on the emergence of elites. Once the initial power structure was established, it attempted to perpetuate itself dynastically by increasing social control and building up familial alliances with other chiefs. Control mechanisms often involved violence. The possibility of using horses—and to lesser extent, camels—as instruments of war determined the success of conquests that would alter the pattern of settlements across Eurasia at the end of the Neolithic. This would at least partially explain how 30 empires or large states that emerged between 3000 and 600 BCE were all found in the Old World, where these animals roamed.
Consequently, tombs with signs of wealth became more abundant in the archaeological record, such as the famous Amesbury Archer, found three miles southeast of Stonehenge in 2002 (near today’s Salisbury) and dated to 2300 BCE. This grave includes more artifacts than any other Bronze Age British burial; besides numerous arrowheads, three copper knives, four boar’s tusks, two stone wrist guards that protected users from their bowstrings, and five pots that conformed to the Bell Beaker tradition, there were two gold hair ornaments—the earliest pieces made of this metal ever found in the British Isles. The arrival of the Bell Beaker complex to the British Isles is associated with an almost complete replacement of the prior local population and subsequent emergence of social elites. The Amesbury Archer must be considered in the context of the spread of metalwork and supraregional exchange networks in a process that archaeologists sometimes call “Bronzization.”
The rise in inequality during this period, both in the Middle East and parts of western Europe, seems to be partly influenced by an increase in population density. This correlation is likely related to a growing complexity in modes of subsistence, trading networks, and political organization associated with population growth.
Although the highest Gini coefficients for past societies determined by the Santa Fe Institute were similar to those found in some present-day European countries (for instance, with values of around 60 in Pompeii and Kahun, an Egyptian settlement from the 12th dynasty), they remained below the values for the most unequal modern societies such as China and the United States (with Gini coefficients of 73 and 85, respectively), which obviously have larger populations.
From a historical perspective this would suggest that an increase in population size brings higher inequality—an issue explored by the economist Thomas Piketty in recent times, but that likely has parallels in Bronze Age populations.
Still, the Gini coefficient cannot always be applied since some settlements have grown with time over the destruction of previous ones, piled one atop another like the layers of a cake. Many ancient sites could not possibly be studied in detail; for instance, at Hisarlik—the old Troy—at least 10 cities arose atop their predecessors in just 2,000 years, making them quite difficult to disentangle. In addition to this limitation, whether the Gini coefficient can be transferred between different cultural, geographic, and ecological environments to make direct comparisons has also been a subject of debate since such factors can influence their inhabitants differently. For example, a settlement established in a jagged terrain would favor smaller, more vertical houses than one extending over a vast plain.
The economic interpretation of past settlements has received some criticism from among the archaeological community; some argue that the quality and solidity of the building materials can be as important as the size of the houses. In our modern cities, we’re all aware that location—for instance, close to the city center—is usually more important than size. Finally, the ostentatious wealth—opulent furniture, wall paintings, mosaics, and so on—that can still be found in some excavated houses such as at Pompeii should be taken into consideration too, though such features aren’t usually well preserved.
One way around these limitations might be to compare the Gini coefficients with the so-called health inequality of each population, since buried human remains are sometimes better preserved than buildings. There are several skeletal indicators (dental cavities, arthrosis, traumas, vitamin deficiencies, etc.) that can reflect the health status of the population in each period. The frequencies of these pathological markers are in general higher during periods of higher inequality.
For example, the 2006–2013 excavation of nonelite cemeteries such as North Tombs Cemeteries at Amarna demonstrated deaths at an early age—mainly of children, teenagers, and young adults—widespread dietary deficiencies, and indications of hard labor, suggesting the poor state of health and substandard working conditions for most of this urban community. For instance, 16 percent of all children under 15 displayed spine injuries of the sort associated with carrying heavy loads; none of them had any grave goods, and sometimes were buried together with several others, with scant regard for the disposition of the bodies — a grim image that contrasts with the glamorous depictions of the pharaoh’s family in the Amarna style.
An additional indicator would be evidence of a high infant mortality rate, although the preservation of children’s skeletal remains is invariably more difficult than that of adult bones due to differential conservation processes, and this could represent an insurmountable bias in the results. Changes in health status can be used to ascertain cultural and ancestral transitions too. In this sense, probably the most striking change observed is between hunter-gatherers and the first farmers in Europe. The latter not only show signs of poorer health—such as cavities, almost unknown by the former—but also higher infant mortality rates and even lower stature than previous hunter-gatherers.
Correlated with this information, recent developments in the stable isotope analysis of carbon and nitrogen ratios in bone collagen can provide information on nutritional status and mobility patterns associated with specific individuals. For instance, the analysis of a high-status burial in Helmsdorf, Germany, related to the Únêtice culture, showed that this person had a higher protein intake than other contemporaneous peers, suggesting as well that diet can be as much an indicator of social status as it is in today’s societies.
Key to understanding the social panorama of the past is that ancient cemeteries can provide not only potential indicators of inequality in the form of grave goods and even differential health status but also genetic material preserved within human remains. The information retrieved from their DNA can be used, for the first time, to correlate ancestry with social power in each period. Furthermore, a crucial aspect of the accumulation of power is the possibility of bequeathing wealth to biological relatives—something that can be tested as well via the interface between genetics and archaeology, which enables us to reveal family links.
Like funerary goods, a privileged resting place could serve as a status marker too. Around 6,500 years ago, the phenomenon of building large funerary stone structures—known as megalithic tombs—emerged, mainly across Europe’s Atlantic seaboard, and culminated in the great passage tomb complexes such as Newgrange in Boyne Valley (Ireland), which has a mound almost 300 feet in diameter and 50 feet high. The origins and meaning of these monuments, which required a heavy investment in labor, have been debated for more than a century, as has the social organization of the farming communities that built them. The genetic analysis of two-dozen individuals found in various megalithic tombs from Scandinavia to Orkney Island and Ireland yielded some interesting social clues.
In some places, notably the British Isles, more males than females were buried in these preeminent spots, pointing to a sex bias. In accordance with this observation, the descent of most individuals with kinship links could be traced through the paternal line. In one case it was possible to find two related males buried in two different megaliths just over a mile apart (Primrose Grange and Carrowmore in Ireland), indicating a geographic expansion of these dominant families. Genetic analyses of skeletal remains discovered within the most intricately constructed chamber of the Newgrange passage tomb revealed that they belonged to the incestuous son of a brother and sister (or a parent and child), and therefore a quarter of his genome had no genetic variation.
This kind of first-degree offspring is extraordinary, only having been cited in royal families of the past headed by god-kings such as the Egyptian pharaohs seeking to maintain a pure dynastic bloodline. (It is known, for instance, that Akhenaten married his eldest daughter, Meritaten, and much later, Ptolemy II married his sister, Arsinoe II—hence his nickname, “Philadelphus” or “sibling loving.”) It has been suggested that this Neolithic elite may have claimed to possess divine powers to ensure the continuity of agricultural cycles by keeping the sun’s movements going.
The findings support the notion that these Neolithic communities were socially stratified and that the massive stone structures were used to bury transgenerational patrilineal members of these clans. Perhaps equally interesting is the fact that in one case relatives were separated by up to 12 generations, pointing to an unusual stability through time of both the funerary tradition and the stratified society where they lived.
One of the most illustrative examples of how the analysis of Bronze Age individuals that lived through continental-scale cultural changes can shed light on the process is a study led by researchers at the Max Planck Institute in Jena and published in 2019. Paleogenetic researchers analyzed more than 100 skeletons from 45 farmstead-related graveyards in the Lech River valley in southern Germany to explore the social mechanisms underlying the local spread of steppe ancestry across Europe. Additionally, isotope data were generated for these individuals to gather information on their lifetime mobility patterns, which could be correlated with differential composition in genetic ancestry.
Isotopic analyses revealed that females tended to be nonlocal (only 50 percent of them had values consistent with the local isotopic range) as compared to males and children from the same cemeteries (where 82 to 84 percent were deemed local). Isotopic data on early and late forming teeth in the same individuals—the first and third permanent molars that emerge at six and 18 years, respectively—suggested that females moved from their birthplaces during adolescence or later. One of them was found to come from a place at least 200 miles away. Most of the males carried the R1b Y chromosome lineage, while the mitochondrial DNA lineage composition was much more diverse. The results indicate that these Bronze Age settlements followed patrilocal residential rules—that is, males stayed in the groups where they were born, while females moved away from them. The fact that most males’ descendants shared their ancestry with a single female also suggests that the social structure, besides being based on patrilineal links, was likely monogamous.
The researchers were able to reconstruct six pedigrees in different graveyards, three of which spanned at least four generations. They detected 10 parent-offspring relationships, six of them between mother and child. Interestingly, the latter were always male; there were no adult daughters present. Again, this suggests that females were interchanged between households as a way to establish alliances; it is likely that their status was secured once they had children in the new household. It was also possible to correlate grave goods (daggers, axes, chisels, and arrowheads for males, and body ornaments such as neck or leg rings for females) with kinship.
This indicates that wealth and social status were inherited and ran with families. The fact that even children who died in infancy were buried with grave goods suggests as well that their status was inherited rather than acquired during their lifetime. A further observation was that members of each clan were buried near each other in the cemeteries, thus clearly delimiting preeminent areas within them. It is likely that the inheritance system of these households was based on male primogeniture—a custom by which the oldest son inherits all the family’s properties at the father’s death. With time, forged alliances granted families access to larger, regional clans—and eventually kingdoms.
An examination of the dynamics between kinship and social inequality can be applied to even more recent periods. The complex interactions underlying extended families and population levels can be better understood in geographically isolated places such as islands. Iceland remains the most studied island from a genetic point of view, mainly due to the efforts of a private company called deCODE Genetics that was founded in 1996 by neurologist Kári Stefánsson.
Iceland, a remote island in the north Atlantic, was first colonized around 874 CE, according to the Landnámabök, or “settlement book,” when the Norse chieftain Inólfr Arnarson arrived in the region of present-day Reykjavik. Over the next 150 years, groups of Viking migrants from Norway along with Celtic women and servants or slaves arrived on the island, establishing themselves on rather isolated farms. By 930 CE, all arable land was already occupied and all the forests were gone. The migratory influx slowed down afterward and almost ceased after the year 1000 CE. This resulted in a population that was small and isolated—yet at the same time big enough to have all the common European diseases and genetic diversity—and it suffered several demographic bottlenecks associated with volcanic eruptions, famines, and epidemics of the plague.
Until 1850, the Icelandic population never exceeded 50,000. The combination of two factors—an isolated population and a well-known genealogical database—makes Iceland an ideal laboratory for detecting genetic variants associated with common diseases that affect not only modern Icelanders but also the rest of Europe, where such information does not exist or the population is too big to make such an approach practical. Over the years, researchers from deCODE Genetics have generated a whole body of data on the genomics of modern Icelanders and also on how the original population was established. By working with uniparental markers from living Icelanders it could be observed that 62 percent of the mitochondrial DNA was Celtic in origin (meaning that the majority of these maternal markers derived from either the British Isles or Ireland), while 75 percent of the Y chromosomes were of Scandinavian origin. This suggested a settlement primarily established by Viking males and Celtic females.
In 2017, and thanks to paleogenomic techniques, it was possible to retrieve 27 ancient Icelandic genomes, most of them from the heathen period (prior to the year 1000 CE, when Icelanders decided to become Christians by the curious procedure of voting). At the nuclear genome level, these pioneers had a Norwegian-type ancestry (55.4 percent) that was greater than the Celtic one, and more prevalent among men (a recent genetic study of more than 400 Viking individuals has confirmed the spread of Norwegian ancestry mainly across the North Atlantic islands).
Modern Icelanders are not, however, a simple mixture of the two components; their ancestry demonstrates a differentiation from the two source populations at least partially due to genetic drift—promoted by geographic isolation—during the last thousand years. Interestingly, the Norwegian-type ancestry component in Iceland is nowadays 70.4 percent, suggesting an increase that was likely socially mediated. An example of this stems from seven individuals excavated in 1964 from a boat grave (a type of burial in which a ship is used as a container of the dead) at Vatnsdalur in the remote western fjords. The grave goods included a knife, 30 beads, a silver Thor’s hammer, a Cufic coin (dated circa 870–930 CE), and various items of jewelry. Three of the four skeletons sequenced showed mostly Scandinavian ancestry. One of these individuals is among the few sequenced early settlers to be genetically similar to modern Icelanders, indicating that he contributed disproportionately to their ancestry.
It seems that the Celtic servants brought to Iceland clearly had fewer opportunities to reproduce. Using isotopic analysis, it was also possible to detect that at least three people—two Scandinavians and one Celt —were first-generation migrants, having spent their childhood outside Iceland. One individual had mixed ancestry, indicating that his parents were from different places. The fact that the Celtic ancestry is still detectable decades after the first settlement also suggests that some kind of social discrimination between the two ancestral groups persisted for a while. After a few centuries, however, the admixing of the two communities was complete, to the point that Iceland has essentially become an extended family with a remarkably uniform population.
We have seen several case studies of past inequality correlating funerary archaeology with genetics that might no longer apply today, where legal regulations (and also the exponential increase of cremations) represent a certain degree of standardization in funeral practices. Nevertheless, an opposite trend could shape the future of the archaeology of death: the trend toward personalized coffins, unconventional funerary memorials, and special grave goods. One way or another, mortuary archaeology will always be an important subfield of this discipline, and one that will need to rely on the hard sciences such as genetics and forensics.
Perhaps one encouraging conclusion is that despite what we have seen on the archaeology of past inequality, societies have been able to evolve and change their social stratifications. One example is Iceland itself; the country has become one of the most egalitarian societies in the world. In 2018, Iceland passed a law that all companies employing more than 25 people will have four years to ensure gender-equal payment because, according to the head of the Equality Unit at Iceland’s Welfare Ministry, “equality won’t come about by itself, from the bottom up alone.”
Carles Lalueza-Fox is Research Professor and Director of the Paleogenomics Lab at the Institute of Evolutionary Biology (CSIC-Universitat Pompeu Fabra) in Barcelona. He participated in the Neanderthal Genome Project and led the first retrieval of the genome of an 8,000-year-old European hunter-gatherer. He is the author of “Inequality: A Genetic History,” from which this article is adapted.