Some central epidemiological and sociological analytical concepts

Concepts on the size of urban and rural settlements relating to epidemiological analysis

The pattern of territorial spread and epidemiological structures of the Black Death are central topics of this book. Epidemiology, in the meaning of how human social behaviour affects the spread of contagion, has clear sociological affinities. The understanding and analysis of a complex and vast epidemiological process that comprises such vast territories and enormous numbers of people depend on good analytical tools, and useful epidemiological and sociological concepts. Additional analytical concepts will be presented and discussed in the introduction to the chapter on the spread of plague in Europe.

To describe and analyse efficiently the pattern and pace of spread of the Black Death requires clear concepts for various types of human settlements adapted to medieval social realities. The concepts of city and town are not unambiguous in ordinary parlance. In the Middle Ages, urban populations were generally much smaller than in modern society but so were populations in general. England contained, for instance, perhaps 6 million inhabitants, Norway around 350,000. In this book, according to medievalist notions and concepts of the relative size of various categories of urban settlements, the concept of town will be used to signify urban centres with 1,000–9,999 inhabitants, the concept of city relates to urban centres with 10,000 to around 100,000 inhabitants. The very few cities with 100,000 inhabitants or more were the metropolises of the Middle Ages.

By implication a village contains less than 1,000 inhabitants and can be subdivided into hamlets with less than around 150 inhabitants (and without a church), small, middle-sized and large villages or townships (manorial population centres).

The concept of city is also associated with any urban centre with a cathedral and resident bishop, whatever its size. In some cases, the use of this concept will be made clear by the term cathedral city.

Basic features of the spread of bubonic plague in local society

Size of settlement affects the time perspective of epidemic developments, from the introduction of an infective rat flea in a rat colony to the transitions into the endemic phase and the fully-fledged epidemic, and its duration.