In 1978 a retired British general published twenty-six pages that should have rearranged how the West understood itself, and did not, because almost nobody who needed to read it ever did.
Sir John Glubb was not an academic, which is probably why he noticed.
He took eleven great empires and measured how long each lasted from rise to the end of dominance. Assyria. Persia. Alexander's successors. The Roman Republic and then the Empire. The Arab Empire. The Mamluks. The Ottomans. Spain. Romanov Russia. Britain.
The average came out at roughly 250 years. Around ten generations.
Those empires span three thousand years. They sit on different continents. They worship different gods, speak unrelated languages, and fight with entirely different technology. Assyria ran on bronze. The Ottomans ran on gunpowder. Britain ran on steam, steel and telegraph cable.
There is no material reason why bronze and steam should produce the same number.
A state that can move an order from London to Delhi in minutes ought to outlast one where the fastest message travels at the speed of a horse.
It does not. Britain got about 250 years. Assyria got about 247.
Whatever is imposing the limit does not care what you have invented. Which means it is not in the equipment. It is in us.
Glubb was careful about the number and I want to be too. The dates are arguable. He said as much himself, and called the pattern remarkable rather than exact.
The structure matters more than the arithmetic anyway, and the structure is where it gets uncomfortable, because he found the same seven phases in the same order every time.
Pioneers, erupting out of poverty and hard conditions with more courage than equipment. Conquest, where the army is the central institution and a talented nobody can rise on ability alone. Commerce, where energy shifts from taking territory to working it, trade networks spread and cities swell. Affluence, the age of splendour, grand buildings and the highest standard of living the system will ever deliver. Intellect, universities, scholarship, argument, the life of the mind at full stretch. Decadence. Then decline.
What runs underneath is the same thing Ibn Khaldun described six centuries earlier, and Glubb had read him: the qualities that build the thing are dissolved by the thing being built.
A society that cannot say what it values cannot defend what it values, and will not notice it has stopped trying.
It is worth asking what year you think it is. Britain's run ends around 1950. The American ascendancy is usually dated from 1776, or from 1945 if you count only dominance.
Do the arithmetic yourself. Glubb declined to, and said it was not his place, and then wrote twenty-six pages that make it impossible not to.