Secular Cycle

Combine these two processes, and you get the basic structure of a  secular cycle. There are about a hundred years of unalloyed growth, as  peasant and noble populations rebound from the last disaster. During  this period, the economy is strong, the people are optimistic and  patriotic, and the state is strong and united. 

After this come about fifty years of “stagflation”. There is no more  room for easy growth, but the system is able to absorb the surplus  population without cracking. Peasants may not have enough land, but they  go to the city in search of jobs. Nobles may not have enough of the  positions they want, but they go to college in order to become  bureaucrats, or join the retinues of stronger nobles. The price of labor  reaches its lowest point, and the haves are able to exploit the  desperation of the have-nots to reach the zenith of their power. From  the outside, this period can look like a golden age: huge cities buzzing  with people, universities crammed with students, ultra-rich nobles  throwing money at the arts and sciences. From the inside, for most  people it will look like a narrowing of opportunity and a  hard-to-explain but growing sense that something is wrong.

After this comes a crisis. The mechanisms that have previously  absorbed surplus population fail. Famine and disease ravage the  peasantry. State finances fall apart. Social trust and patriotism  disappear as it becomes increasingly obvious that it’s every man for  himself and that people with scruples will be defeated or exploited by  people without.

After this comes the depression period (marked “intercycle” on the  graph above, but I’m going to stick with the book’s term). The graph  makes it look puny, but it can last 100 to 150 years. During this  period, the peasant population is low, but the noble population is still  high. This is most likely an era of very weak or even absent state  power, barbarian invasions, and civil war. The peasant population is in a  good position to expand, but cannot do so because wars keep killing  people off or forcing them into walled towns where they can’t do any  farming. Usually it takes a couple more wars and disasters before the  noble population has decreased enough to reverse elite overproduction.  At this point the remaining nobles look around, decide that there is  more than enough for all of them, and feel incentivized to cooperate  with the formation of a strong centralized state.