Classical Empires

By the last few centuries BCE, the small kingdoms and city-states of the Axial thinkers were being swallowed, almost everywhere, by something larger and hungrier: the empire. From the Atlantic to the Pacific a chain of vast states now rose, each welding many peoples together under one law, one army, and one network of roads, and for the first time in history they reached far enough to touch. A bolt of silk could pass, hand to hand along the caravan tracks we now call the Silk Road, from the Han court in China through the Persian lands to a senator's wife in Rome, and with the silk went ideas, faiths, inventions, and plagues. The classical age is the moment the Old World first became, faintly but really, a single connected place.

Each of these empires was a marvel of organized power. Persia, under Darius, ran a road with royal couriers so fast that Herodotus's praise of them, that neither snow nor rain nor heat nor gloom of night stayed them, is carved today over a post office in New York. Rome laid more than eighty thousand kilometers of engineered highway, raised aqueducts that carried mountain water across whole provinces on arches still standing two thousand years later, and poured a concrete so good, self-healing, and durable in seawater that we spent much of the twentieth century trying to rediscover how they made it. In China, the first emperor unified the warring states by force, standardized the very width of cart axles and the strokes of the writing, and left a buried army of eight thousand life-sized clay soldiers to guard him in death, while the Han who followed invented paper, the seismograph, and a civil service chosen, in principle, by examination. In India, the emperor Ashoka, sickened by his own conquests, converted to Buddhism and carved edicts of tolerance and compassion into rock across his realm. These were among the most sophisticated societies the world had yet produced.

And they were engines of knowledge as much as of war. At Alexandria, on the Egyptian coast, the Greek rulers of Egypt tried something audacious and new: to gather, under one roof, all the knowledge in the world. The Library of Alexandria drew scrolls and scholars from across the known earth, and there Greek minds measured the circumference of the planet to within a few percent, mapped the stars, and laid the foundations of geometry and medicine that would serve for millennia. We should hold up one object from this world in particular, because it shatters our easy condescension toward the ancients. In 1901, sponge divers pulled from a Roman-era shipwreck near the island of Antikythera a corroded lump of bronze that turned out to be a machine: a hand-cranked device of at least thirty interlocking gears that modeled the motions of the Sun, Moon, and planets and predicted eclipses, an analog computer built around the first century BCE. Nothing of comparable complexity is known again for well over a thousand years. The people of the classical world were not simple. They were us, with different tools.

Consider just how far that reach extended. Around 240 BCE the scholar Eratosthenes, who ran the Library, heard that at noon on the summer solstice the sun shone straight down a well in one Egyptian town while still casting a shadow in another to the north. From nothing more than the length of that shadow and the distance between the towns, he calculated the circumference of the whole round Earth, and got it right to within a few percent, without ever leaving Egypt. Archimedes of Syracuse worked out the principle of the lever, pinned down the value of pi far more tightly than anyone before him, and reached the very threshold of the integral calculus nearly two thousand years before Newton. In India, across these centuries, mathematicians were perfecting the place-value number system and moving toward a true symbol for zero, the quiet conceptual leap that makes all modern calculation possible and that Europe would not adopt for another millennium, still calling the digits "Arabic" because they arrived by way of the Arab world, which had them from India. This was not a world fumbling in the dark. It was a world doing real, cumulative, often dazzling science, and a great deal of what it learned would soon have to be painfully rediscovered, because it was about to be lost.

We will be honest here, because this is fertile ground for fantasy: the Antikythera mechanism is entirely real, securely dated, and genuinely astonishing, and it sits at the sober end of a long shelf of "ancient technology" claims whose other end runs into wishful thinking. Some of the famous puzzles, a clay jar from Baghdad imagined as a battery, a carved bird supposed to be a glider, a temple relief read as an electric lamp, dissolve on close inspection into ordinary objects wearing extraordinary interpretations. The true marvel needs no embroidery. Roman concrete, Chinese paper, Greek gears, and Indian steel that resisted rust for sixteen centuries are wonder enough, and they are true.

Yet running through all this brilliance is a shadow this book has learned to watch for. The classical world told, at its heart, a story about knowledge that it could not stop retelling, the story of Prometheus: the Titan who stole fire from the gods and gave it to humankind, and for that gift, that theft of divine knowledge, was chained to a rock to have his liver torn out by an eagle for eternity. It is the serpent of the last chapter in a Greek robe, the same ancient intuition that the knowledge which lifts us is somehow stolen, forbidden, and dangerous to the one who brings it. And the empires proved the intuition had teeth. The same Chinese emperor who unified the world is remembered for ordering the burning of the books and, it was said, the burying alive of the scholars who kept the old learning. The great Library of Alexandria, the dream of gathering all knowledge, declined and was pillaged and burned across centuries of war and zealotry until it was simply gone, and with it an incalculable portion of everything the ancient world had learned. Rome had a formal ritual, damnatio memoriae, for erasing a disgraced person from history, chiseling their name from every monument. Power had always known that to control people you must control what they are allowed to know, and remember.

That knowledge, the knowledge of how to erase knowledge, was about to be turned on the classical world itself. The empires would fall or transform, the open and crowded marketplace of gods and philosophies would close, and a new kind of order, singular, absolute, and jealous, would rise in its place and hold the West for a thousand years.