Additional factors facilitating the spread of disease are the movements of armies and the expansion of international trade. The latter factor should be qualified by noting that international trade expands in the precrisis period (stagflation phase) and then gradually declines after the society has descended into anarchy. Thus, the rise of

Thus, we can use trends in higher education as an index of intraelite competition (Goldstone 1991:123).

Impoverished elites could also improve their incomes by attaching themselves to the retinues of powerful magnates.

To maintain their income, the lords attempted to extract a greater amount from each peasant, as well as trying to dispossess one another (via brigandage and internal warfare).

for a new secular cycle to get going, the pressures of the general population on resources and of the elites on commoners must be substantially reduced from their precrisis levels.

Malthus pointed out that when population increases beyond the means of subsistence, food prices increase, real wages decline, and per capita consumption, especially among the poorer strata, drops.

Rents would rise first, with grain prices lagging behind rents, the price of industrial goods lagging behind grain prices, and workers’ wages bringing up the rear.

There must also be some vulnerability of the state in the form of internal divisions and economic or political reverses. Otherwise, popular discontent is unvoiced, and popular opposition is simply suppressed.

the social structure, the most important part of which was the surplus-extraction relationship between the direct producers and the ruling class (Brenner 1985a:10–11).