The forgotten revolution

257-132 BCE


Here’s where this number comes from: Take a sequence of symbols, (a b c d e f g h i j), say. Construct as many groups as you want by sticking parentheses around any two or more symbols or groups. For example, ((a b) c d (e (f g)) h i j). Or (a (b (c (d e f g) h) i) j). Or (a (b (c d e)) f g (h i j)). There are 103,049 ways of doing this with ten symbols, so 103,049 is the tenth Schröder number, named after the man who published this result in 1870. But it turns out that the same number is given in Plutarch – attributed to Hipparchus (190-120 BCE) – as the number of “affirmative compound propositions” that can be made from ten simple propositions. It is only in 1994 that somebody connected the dots, and realized that Schröder numbers had been discovered 2000 years before Schröder.

This is just one example of the very high level of mathematical, scientific, and technical accomplishment attained within the Hellenistic world — the world of Greek culture after Alexander. Lucio Russo calls Hellenistic science The Forgotten Revolution. A couple more examples from his book:

Everybody knows that Aristotle – and thus “the Greeks” – thought that heavy objects fall faster than light ones. Supposedly it took Galileo to prove him wrong. But in fact there is a clear statement in Lucretius (De Rerum Natura II:225-239) that objects of different weight fall at the same speed, unless air resistance kicks in; Russo argues that circumstantial evidence points to Hipparchus as the source.

Russo also argues that Hellenistic thinkers understood that gravity could account for the spherical shapes of the earth and planets, and that the balance between gravity and linear velocity could account for circular orbits. He shows that some strange passages in Vitruvius and Pliny about the sun making planets go around by shooting out triangular rays make sense if you assume the authors were looking at, but not understanding, vector diagrams of successive straight line motions bent into a circle by a centripetal thrust.

Russo argues that scientific progress largely came to an end by 150 BCE, and the Roman period saw an actual decline in scientific understanding. Later writers like Ptolemy and Galen, often taken to represent the height of Classical learning, were derivative, and didn’t really understand their predecessors: a stark reminder that a civilization may avoid collapse, and even maintain a decent level of prosperity, but regress intellectually.


Asabiya and metaethnic frontiers

In 390 BCE an army of Gauls, 30 thousand strong, marched out of northern Italy into Latium, an area that included Rome. They defeated a Roman army, sacked and burned Rome, and left only after being paid a large tribute. This marked a turning point for Rome, which resolved never again to allow such a disaster. Over the next century, Romans used a mixture of coercion and consent to bind their Italian allies more closely to them. Attempted secession was punished. But those who accepted their position as allies were not simply crushed and plundered (as in many other empires) but granted some or all of the privileges of Roman citizenship in return for military contributions. Membership in the Roman confederation was attractive enough that many Italian states sought it voluntarily.

The history of Greece during this period is different. Greek city-states never united. In the aftermath of the bloody Peloponnesian war, different city-states went on fighting for supremacy, until they were finally conquered by an outside power, Macedonia.

Peter Turchin is an ecologist-turned-social scientist who thinks that the contrast between Rome and Greece illustrates some general laws of history. According to Turchin, the rise and fall of empires is partly conditioned on the strength of “asabiya,” or social solidarity. (He borrows the term from the medieval Arab historian ibn Khaldun.) The strength of states depends not just on material factors like population size and wealth, but also on morale – on the willingness of citizens to work together for the common good (which includes punishing free-riders). Asabiya was high in early Rome; in Greece, by contrast, while individual city-states might evoke strong group feeling, there was little willingness to cooperate for the good of Greece as a whole.

metaethnicAsabiya in turn (according to Turchin) develops especially along “metaethnic frontiers,” where very different cultures meet and clash. The illustration (by me, not Turchin) shows the general idea. When culture changes little, or changes gradually, with distance (a), there is little basis for uniting independent polities (stars) into enduring larger units, and alliances (dotted lines) shift constantly. Along the metaethnic frontier (b), the opposite is true (solid lines). Think Game of Thrones versus Lord of the Rings: it’s easier to get men and elves and dwarves to work together when they are fighting an army of orcs serving the Dark Lord.

Sometimes a metaethnic frontier develops where major religions or ideologies clash. But in the Roman case, the metaethnic frontier ran along the line dividing civilized Italians from barbarian Celts. Greece, by contrast, experienced a surge in fellow-feeling when Athens and Sparta fought together to defeat Persia, but this was too short lived to lead to a unified state.

Also worth reading is Empires of Trust, tracing parallels between the expansion of early Rome and of the United States – two immense states on the western frontier of civilization. (The book is better than most comparing America and Rome.)

State patriarchy and the Ancient City

677-539 BCE

The period leading up to historical times saw the rise of patrilineal descent groups (and maybe some transitions from matrilineal descent) across Eurasia. Different civilizations found different ways of accommodating these groups. In China, patrilineal clans go as far back as we have any historical records, back to the Shang dynasty. Confucius (551-479 BCE) in some ways represented a break with this past. He thought a wise prince should select ministers based on their ability rather than their lineage. But China could never be governed by bureaucrats alone, and Chinese states found themselves depending on extended families and clans to help rule the country. The Confucian state exalted filial piety, obedience to one’s elders, and ancestor worship along with obedience to the Emperor. When an official told Confucius “In my country there is an upright man named Kung. When his father stole a sheep, Kung bore witness against him,” Confucius replied, “The upright men in my community are different from this. The father conceals the misconduct of the son. The son conceals the misconduct of the father. Uprightness is to be found in this.” The resulting social compact – Arthur Wolf, an anthropologist of China calls it “state patriarchy” – was extraordinarily resilient. In days to come we will see how it kept bouncing back from one disruption after another, like one of those heavy-bottomed dolls you just can’t keep knocked over.

By contrast, the classical city-states of Greece and Rome went through a series of social revolutions early in their history where both kings and patrilineages lost their exalted position. This argument was developed back in the nineteenth century by the French historian Numa Denis Fustel de Coulanges. In his book The Ancient City, Fustel showed how ancestor worship and clan loyalty gave way to civic institutions. For example in Athens the democratic reformer Cleisthenes (570-508) replaced old-style subdivisions of the populace based on descent with new subdivisions based on residence. For a time, the classical city-state commanded intense loyalty from its citizens, and displayed an exceptionally high level of military effectiveness.

China’s revolution against the old order of elders, extended family, and clan waited until the twentieth century, and took a horrific toll on the population. Even today some of the old ways persist. The putative patrilineal descendants of Confucius, more than two million strong, have recently been updating their genealogies.


Like the traditional poetry of other peoples, the traditional poetry of the Greeks celebrated the Heroic Age. This was the time when men were bigger and stronger, and they performed marvelous feats of prowess. Their weapons were made of bronze and not of iron, and they were ruled by kings. … The Heroic Age came to an end in two great wars – the Theban and the Trojan. … This was how the Mycenaean Greek civilization of the second millennium BC was remembered in historic Greece.

Margalit Finkelberg. Greeks and Pre-Greeks

Classical Greek poetry concerned with the Heroic Age includes a lot of genealogy, with an emphasis on descent in the male line, much like the begats in the Bible. Modern readers familiar with the Iliad and Odyssey find this stuff pretty boring, but it mattered a lot to the Greeks, who would try to link their existing patrilineal clans to the legendary family lines of the Heroic Age.

An emphasis on patrilineal descent is a general feature of early Indo-European society and its later offshoots, including the Greeks; the Indo-European expansion is one phase of the Patriarchal Age, leaving its imprint particularly on the distribution of Y chromosome variants. But given this patrilineal focus, there is something odd about the legends of the Heroic Age. In virtually none of the surviving legends do we find kingship passing from father to son, even when there is a son around. Instead, the normal pattern is that the king’s successor is the guy who marries his daughter – in other words his son-in-law, not his son. Meanwhile, the king’s son has to marry elsewhere. (Although the legends seem to present some cases of rotating succession, where multiple patrilineages took turns marrying into a matrilineage. In these cases, a king’s grandson might marry back into the kingdom, marrying his father’s sister’s daughter.) The implication is that the line of succession to the throne ran from mother to daughter, although it was the husbands of these women who actually exercised power: kingship by marriage. The most notable case of a son succeeding to his father’s throne is the exception that proves the rule: Oedipus got to be king of Thebes because he married Queen Jocasta, not because he was King Laius’ son. (Spoiler alert: see below*)

In Greeks and Pre-Greeks: Aegean Prehistory and Greek Heroic Tradition, Margalit Finkelberg argues that legends of the Heroic Age are memories of a time when the patrilineal traditions of the Greeks coexisted with earlier matrilineal traditions. More specifically, she argues that matrilineal Pre-Greek cultures were associated with the Anatolian language family, the first branch off the Indo-European tree, which also includes Hittite. On her account, Greece looks like ancestral Polynesia, a society flipped from matrilineal to patrilineal by invaders.

Finkelberg is not the first person to notice possible survivals of matrilineal descent from before the coming of the Indo-Europeans and other folk. Such survivals led some nineteenth century scholars to theorize that matrilineality – tracing descent and succession through the female line – was a stage of social evolution that all societies passed through. Some scholars also believed that matrilineal societies were matriarchal – ruled by women. Neither of these theories has held up very well. And yet …

… based on reconstructions of cultural phylogeny and/or ancestral vocabulary a number of the great demic expansions that covered the world seem to have started out matrilineal and/or matrilocal. The list (labelled by associated language families) includes:

So although matrilineal/matrilocal organization is not a stage that every society passes through, it is seems to be a phase in many demic expansions. This is actually not too surprising. One solid finding in the anthropology of kinship is that matrilocal societies, in which a man goes to live with his wife’s kin when he marries, tend to be internally peaceful, without a lot of feuding between neighboring villages in the same tribe. This makes sense, since the men are no more related to the men in their own village than they are to men in neighboring villages. At the same time, matrilocal societies are often quite war-like with respect folks outside the larger tribe (just ask the neighbors of the Iroquois or the Navajo). Since matrilocality and matrilineality (which tend to go together) are associated with internal peace and external aggression, this social organization is well-suited to life along an ethnic frontier. Matrilocality (which is strongly associated with matrilineality) is one way tribal societies generate the social solidarity that enables demic expansion.

But there are several limits to matrilocal solidarity. First, the introduction of stock herding tends to undermine matrilocality and matrilineality. (My late colleague Henry Harpending worked with a group, the Herero in southern Africa, who had taken up cattle herding, and were probably in the early stages of transition from matri- to patrilineal.) Also matrilocal/matrilineal societies rarely exceed a few tens of thousands of people. Beyond that size their internal unity tends to break down, and parents start insisting that married sons stick around to defend the homestead. So a lot of the later, better known population expansions, including Indo-European, Semitic, Turkic, and Han Chinese are heavily patrilineal. But even today, traces of earlier matrilineal social organization still survive in some places – in the matrilineal belt of Central Africa, and in some of South East Asia, where patrilineality, and mate guarding to secure the male line, mostly don’t reach the same intensity as in much of Asia.

* Oedipus didn’t know it, but Jocasta was his mom.

Weaving history

834-678 BCE.

The association of particular plaid patterns (tartans) with particular Scottish highland clans is a phenomenon of the last several centuries. But the Celt-plaid connection goes back a lot farther than that.


This picture shows a scrap of fabric associated with the Iron Age Hallstatt culture of central Europe. The culture lasted from 800-500 BCE, and is ancestral to later historic Celtic cultures. In fact, traditions of plaid weaving seem to go back a lot further. We find similar plaids being woven at roughly the same time, but thousands of miles away, in what is now Xinjiang province in western China. Linguistic evidence (from later writing) and genetic evidence (from mummies) suggest that the inhabitants of Xinjiang at this point were speakers of Tocharian languages, a branch of Indo-European, deriving from the western steppes. (Both Tocharian and Celtic probably branched off the Indo-European tree long before Indo-European-speaking chariot riders rode south to Iran and India.) We know that Proto-Indo-European had words for weaving. The Celtic and Tocharian plaids are similar enough (according to those who know such things) that it seems likely that IE speakers were also weaving plaids from early on.

The Mediterranean developed its own culture of weaving. In Mycenaean Greece, slave women worked under factory-like conditions to produce cloth for ordinary wear, some of it exported. Aristocratic women too were weavers. They might work with spindles of bronze, silver, or gold, weaving story cloths – tapestries that illustrated family histories. The shroud that Penelope wove by day and unwove by night was presumably one such.

Mycenaeans used writing for bureaucratic record keeping, not story-telling. Remembering the past was the business of female weavers and male bards. When literacy disappeared during the Greek Dark Age, historic memory, such as it was, was kept going by weavers, and by bards – often called weavers of words.

The world at 1000 BCE

Logarithmic History today covers 1000-835 BCE. Here’s a quick look at the world around 1000 BCE

The world population is about 50 million.

The Bantu expansion is just beginning, from a homeland on the present Nigeria/Cameroon border. It will eventually cover most of Africa south of the equator. The expansion is sometimes told as a story of first farmers replacing hunter-gatherers. But, as with the Indo-European expansion, this now looks to be too simple. Other farmers and herders reached east Africa before the Bantu; traces of their languages survive as eastern Bantu substrates. So the Bantu had something extra – social organization? malaria resistance? – going for them.

Seafarers with roots in the Lapita culture have already reached Western Polynesian – Samoa and Tonga, previously uninhabited.

The Olmec are flourishing in Meso-America. A controversial find (the Cascajal block) suggests they are just taking up writing.

In China, the Mandate of Heaven has passed from the Shang Dynasty to the Zhou.

In the Near East and Eastern Mediterranean, the Late Bronze Age collapse has opened up space for smaller states. Tyre and other Phoenician city-states are sailing the Mediterranean. Phoenicians using an alphabet that Greeks will eventually adapt. Further south, Philistines and Israelites have been duking it out, with Israelites gaining the upper hand under David* (king from 1010 to 970 BCE). The Iron Age conventionally begins now, with the widespread use of iron – more abundant and cheaper than bronze.

On the steppe, horses have long been domesticated, but people are now learning to make effective use of cavalry – fighting in formation and firing volleys from horseback. This is the beginning of 2500 years in which the division between Steppe and Sown will be central to Eurasian history.

* Everybody knows that David killed Goliath (1 Samuel 17). However, according to 2 Samuel 21:19, Goliath was killed by Elhanan of Bethlehem. Probably the Elhanan story is the original one, and the whole David-and-Goliath story amounts to later resume-padding on the part of David at the expense of a subordinate. See The Historical David: The Real Life of an Invented Hero for this and other demonstrations of how we can recover likely truths from historical texts.

The fall of Troy

1360-1176 BCE

Those who had dreamed that force, thanks to progress, belonged only to the past, have been able to see in the Iliad a historical document; those who know how to see force, today as yesterday, at the center of all human history, can find there the most beautiful, the purest of mirrors.

Simone Weil, “The Iliad, or the Poem of Force,” 1940-1941

Some things we know (probably) about Late Bronze Age Trojans and Greeks.

  • Troy is represented by the archeological site of Hisarlik, in Turkey near the Dardanelles. It covered over fifty acres and probably had a population in the high thousands. The kingdom of Troy was a client state of the Hittites, known to them as Wilusa (Greek Ilion).
  • Troy was devastated around 1300 BCE, probably by an earthquake, and again, just after 1200 BCE, by fire. There are earlier episodes of destruction as well.
  • The Hittites knew a kingdom to their west called Ahhiyawa. The Ahhiyawans were the people known to Homer as the “Achaians,” i.e. the Greeks. The Egyptians knew a kingdom to their north, beyond Kefta (= Crete = Biblical Kaphthor), called Danaja, whose chief cities match those of Mycenaean Greece. The Danajans probably correspond to the “Danaans,” an alternative Homeric name for the Achaians. Ahhiyawa/Danaja may have been a single state, with vassals under the rule of a “King of Kings,” capitol Mycenae.
  • Homer probably composed the Iliad in the eighth century BCE (762 BCE, give or take 50 years, according to recent research applying evolutionary models to the text). But he relied on sources – presumably earlier oral poems – that went back centuries earlier. The names he gives for the Greeks were not current in his own time. Many lines of his epics only scan if he was drawing on poetic formulas from a Bronze Age dialect of Greek. The cities he lists among those who contributed to the war effort match the Bronze Age better than his own time. And he is familiar with Bronze Age helmets and shields that had long since gone out of use.

So the story of the Trojan war dates back to the Bronze Age, and incorporates real geography and material culture. Just how true the story itself is less certain. It has had an enormous influence of course. Geoffrey of Monmouth claimed that England’s first king was a descendant of refugees from fallen Troy. Sultan Mehmet II claimed to be avenging the Trojans when he conquered Constantinople in 1453.

There a many books on the Trojan War (apart from the ones by Homer). Here are some good ones.

And a remark on war in the lives of ants and men.