Roman Secular Cycle

Discussion

Scott Alexander:

"Eight chapters are case studies of eight different historical periods and how they followed the secular cycle model.

For example, Chapter 7 is on the Roman Empire. It starts with Augustus in 27 BC. The Roman Republic has just undergone a hundred years of civil war, from the Gracchi to Marius to Sulla to Pompey to Caesar to Antony. All of this decreased its population by 30% from its second-century peak. That means things are set to get a lot better very quickly.

The expansion phase of the Empire lasted from Augustus (27 BC) to Nerva (96 AD), followed by a stagflation phase from Nerva to Antonius Pius (165 AD). Throughout both phases, the population grew – from about 40 million in Augustus’ day to 65 million in Antonius’. Wheat prices stayed stable until Nerva, then doubled from the beginning of the second century to its end. Legionary pay followed the inverse pattern, staying stable until Nerva and then decreasing by a third before 200. The finances of the state were the same – pretty good until the late second century (despite occasional crazy people becoming Emperor and spending the entire treasury building statues of themselves), but cratering during the time of Marcus Aurelius and Commodus (who debased the denarius down to only 2 g silver).

Throughout expansion and stagflation, the Empire was relatively peaceful (the “Pax Romana”). Sure, occasionally a crazy person would become Emperor and they would have to kill him. There was even one small civil war which lasted all of a year (69 AD). But in general, these were isolated incidents.

Throughout the expansion phase, upward mobility was high and income inequality relatively low. T&N measure this as how many consuls (the highest position in the Roman governmental hierarchy) had fathers who were also consuls. This decreased throughout the first century – from 46% to 18% – then started creeping back up during the stagflation phase to reach 32% at the end of the second century.

The crisis phase began in 165 AD at the peak of Rome’s population and wealth. The Antonine Plague ravaged the Empire, killing up to 30% of the population. Fifteen years later, the century-long dominance of the Good Emperors ended, and Commodus took the throne. Then he was murdered and Pertinax took the throne. Then he was murdered and Didius Julianus took the throne. Then he was murdered and Septimius Severus took the throne.

Now we are well into the disintegrative trend, and the shorter 40-60 year cycle comes into play. Septimus Severius founds a dynasty that lasts 41 years, until Septimius Alexander (the cousin of the grandson of Septimius Severus’ sister-in-law; it’s complicated) was assassinated by his own soldiers in Germany. This begins the Crisis Of The Third Century, a time of constant civil war, mass depopulation, and economic collapse. The Five Good Emperors of the second century ruled 84 years between them (average of 17 years per emperor). The fifty year Crisis included 27 emperors, for an average of less than 2 years per emperor.

Finally, in 284, Emperor Diocletian ended the civil wars, re-established centralized authority, and essentially refounded the Roman Empire – a nice round 310 years after Augustus did the same. T&N mark this as the end of a secular cycle and the beginning of a new integrative trend.

T&N are able to tell this story. But they don’t just tell the story. They are able to cite various statistics to back themselves up. The Roman population statistics. The price of wheat and other foodstuffs. The average wages for laborers. They especially like coin hoards – the amount of buried treasure from a given period discovered by treasure-hunters – because they argue you only bury your money during times of instability, so this forms a semi-objective way of measuring how unstable things are."

(https://www.lesswrong.com/posts/2weRdcvqANDq3zdPH/book-review-secular-cycles)