Monogamy and the Making of Western Civilisation
The institution of monogamy in Classical Greece may have led to a host of phenomena that shaped the modern West: from individualism and abstract thinking to liberalism and democracy.
Could polyamory be on the rise? A November 2023 study found that a third of heterosexual British men were open to having more than one partner, and so—more surprisingly—were 11 percent of women. But how many of us are actually polyamorous? Another recent study found that only 2.4 percent of Canadians were currently in a polyamorous arrangement, though fully a fifth reported some experience of open relationships. That study also found that polyamorists tend to be young, and polyamory certainly seems to be growing more popular among educational and social elites. (The most notorious example of an egg-headed polyamorist close to the levers of power is probably Neil Ferguson, who was caught breaking COVID rules to visit his lover—who is also his friend’s wife—not long after his epidemiological modelling played a key role in sending the world into lockdown.)
It’s not hard to see why polyamorists in traditionally Christian societies view themselves as a daring vanguard, bravely testing the boundaries of convention. A deeper look at the history of the practice, though, reveals that they may be the ultimate reactionaries. It was largely Christianity that brought the real revolution in Western family structure to fruition, a revolution that may have paved the way for other Western innovations, from equal citizenship rights to liberalism itself. To understand this fully, we need go back beyond Christianity to classical Greece and Rome, where the true origins of Western monogamy may lie.
We should not underestimate just how historically unusual monogamy is, especially in the strict form that has long been seen as normative—and normal—in the West. Only 16 percent of the societies listed in the standard Ethnographic Atlas are described as monogamous. Even the looser form of monogamy that was practised in ancient Greece and Rome—where men could have extra-marital sex with other free men, with slaves, and with a variety of different sorts of sex-workers, but were only allowed to have one wife—is highly unusual. The form of monogamy mandated by the Christian Church, in which men were expected to restrict their sexual activities to their wives, is even more so. Many non-Christian countries only outlawed polygamy in the twentieth century under moral pressure from the West. China did not ban the practice until 1953.
Marilyn Simon
In other words, the sexual and family mores that most of us were raised with are not only distinctly odd, but also thoroughly WEIRD, to employ Harvard anthropologist Joseph Henrich’s acronym for Western, Educated, Industrialised, Rich, and Democratic societies. In Henrich’s account of the West, strict monogamy was only one of a broader package of norms to do with marriage and the family that were gradually inculcated by the Christian Church during the Middle Ages. These norms made it more difficult for Westerners to maintain the kinds of extended kinship networks that are pervasive in other parts of the world. And that, in turn, helped stimulate sociability with non-kin others in the West—something that, for Henrich, had wide-ranging repercussions for Western psychology, politics, and economics.
Henrich’s theory, buttressed by a wide range of empirical scholarship from psychology, sociology, and economic history, restores Christianity to a central place in the development of the West. As we have seen, though, a form of monogamy was already practised in ancient Greece and Rome, and it is Greco-Roman societies that may have provided the decisive break with the polygamous past, bequeathing to Christianity a set of sexual norms that it could later tighten. If this is right, monogamy is an inheritance from the Greco-Roman past that helped make the West distinctive.
For Walter Scheidel, Greece and Rome are the two earliest societies that we know of with what he calls “socially-imposed universal monogamy.” Perhaps the most striking aspect of its universality was that this norm of monogamy applied even to elite men, including kings and emperors—in strong contrast to the ancient civilisations of the Near East and China, whose rulers maintained extensive harems. Roman emperors could have multiple consecutive wives—Claudius, for example, had four, and Elagabulus had three over the course of three years—but one after the other, never at the same time. (King Henry VIII would face the same limitation in sixteenth-century England.)
In classical Greece, polygamy was viewed as “a barbarian custom or a mark of tyranny,” as Scheidel puts it. Dionysius I, the tyrant of Syracuse, had two wives. Philip II of Macedon adopted many Greek customs, including pederasty, in his desperation to be accepted as a Hellene, but he was not going to limit himself to one wife at a time. His son Alexander followed his father’s example, as did many Hellenistic warlords and kings.
Monogamy, on the other hand, may have been a feature of Athens’ democracy from the time of Solon, who reformed the city’s laws in the early sixth century BC. By making only children born in wedlock legitimate for the purposes of citizenship and inheritance, Solon disincentivised the fathering of children with concubines—something that had been popular among aristocratic males. For Susan Lape, the change put every free Athenian “on the same reproductive footing,” which helped foster “an egalitarian ethos among men” and constituted “an important condition” for the full democratisation that would come at the end of the sixth century thanks to another reformer, Cleisthenes. Solon may also have introduced other measures designed to shore up sexual equality among male citizens, including—according to one fragment of a piece by the comic poet Philemon—state-sponsored brothels, which Philemon praises as dēmotikos or “democratic.”
It was probably in democratic or proto-democratic Athens, then, that the seeds of Western monogamy were originally planted. Granted, Western monogamy still had a way to go before it attained the strict form it took in the Christian Middle Ages. It was Christianity, after all, that first extended the norms of sexual fidelity that had previously only applied to married women to their husbands as well. But it was the Greeks who first seem to have imposed the same marital norms on elite men as applied to poorer, lower-status citizens.
William Buckner
And it is this limitation on the number of elite men’s spouses that is at the heart of monogamy’s egalitarianism. Imagine a society with one hundred men and one hundred women. Imagine further that each of the ten most powerful males takes four wives, the traditional upper limit in Islamic societies. This is actually quite a modest number: Brigham Young had more than fifty wives, the Mughal Emperor Akbar at least a dozen, and the current Fon of Bafut, the ruler of a part of Cameroon, has nearly a hundred. Even so, the social consequences of even a modest level of polygyny are significant. Given that the ten highest-status men have together taken forty wives, that leaves only sixty women for the remaining ninety men. Even if all the other men only marry one woman each, that still leaves the bottom 30 percent of men without a spouse.
This kind of sexual underclass of males without access to reproductive partners is a recipe for instability, since young, unmarried men account for a disproportionate amount of violent crime. The flipside of this is that monogamous societies, in which far fewer men are wifeless, tend to have high levels of social cohesion, partly because fatherhood lowers men’s testosterone levels.
For Scheidel, the high levels of inter-male cooperation that were a feature of ancient city-states like Athens and Rome were only possible because monogamy had dampened male sexual competition. It is not out of the question, then, that Rome’s conquest of the ancient Mediterranean world was the result, not of outstanding individual manliness—what the Romans called virtus—but of a reduction in masculinity and a corresponding increase in teamwork.
Indeed, if we follow Henrich, monogamy may have helped stimulate the development of a whole host of phenomena that we associate with the modern West, from individualism and abstract thinking to liberalism and democracy.
This brings us back to our current situation. From a purely liberal perspective, there seems to be nothing wrong with one man choosing to have several girlfriends or with several women choosing to share one boyfriend, as long as everyone involved is a consenting adult. (Nor does there seem to be anything wrong with one woman choosing to have multiple boyfriends, though polyandry is vanishingly rare among human societies.)
Even from a feminist perspective, polyamory seems difficult to unambiguously condemn. There is an argument, of course, that women will be treated with more respect and affection in monogamous relationships, and that multiple women having to share one man is an affront to the equality of the sexes that modern societies usually strive to uphold. (Given the way that polyamorous societies tend to lean, relatively few men will be expected to share one woman.) On the other hand, though, many women may genuinely prefer to share the affections and resources of an extremely successful man rather than monopolise those of someone less impressive. Can restricting women’s own sexual preferences and choices really be considered feminist?
But although polyamory doesn’t obviously conflict with either liberalism or feminism, it may weaken the strict, universal monogamy that has been a feature of the West since Greek and Roman times. And that could jeopardise the whole package of Western modernity—including liberalism itself, as well as egalitarianism and even democracy. The liberal mindset that may underpin the increasing acceptance of polyamory in elite circles in the West may thus contribute to the erosion of one of the key social practices that enabled the West to become liberal in the first place.
But fears of this sort may be exaggerated. As late as the nineteenth century, Protestantism was associated with higher literacy, presumably because of its emphasis on sola scriptura as the path to salvation. But the fact that Protestantism spearheaded the surge towards near-universal literacy rates doesn’t mean that societies have to be Protestant in order to be literate. Other societies—including non-Christian ones—have noticed the enormous benefits that flow from literacy and have cultivated it on that basis. And even in formerly Protestant societies, parents have not stopped insisting on their children learning to read as Protestant religiosity has declined.
It may be, then, that a sense of the social benefits of monogamy will limit polyamory’s spread in Western societies even as Christianity declines. Perhaps having multiple simultaneous partners will be come to be viewed as akin to polluting the environment—a certain amount of polyamory will be tolerated, but too much will cause a backlash. On the other hand, in the absence of religious commitments, it seems unlikely that many high-status men will agree to have fewer partners than they could have, or that all modern, empowered women will prefer keeping an underwhelming man to themselves rather than sharing somebody more interesting with other women. So if polyamory is on the rise, will this lead to a less egalitarian and cohesive society, one threatened by an underclass of incels only partially sated by VR porn? Will a coming collapse of Western monogamy bring the whole edifice of modern Western civilisation down with it? It certainly seems unlikely. But we may be about to find out.
