Historical Demography

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Historical demography is the quantitative study of the size and structure of past populations, the components of population change (fertility, mortality, and migration), and the factors that influenced them. In its broadest sense, historical demography covers the entire history of the human species, but for prehistoric populations, estimates of population size and structure must rely on intelligent guesswork, based on archaeological studies of material remains such as skeletons, dwellings, and cooking utensils. Even in the case of populations with written records but with no census of population or registration of births and deaths, population size can only be estimated approximately, using inscriptions on gravestones, legal documents, and taxation records.

In Europe, ecclesiastical records of baptisms, marriages, and funerals serve as proxies for civil registration from the sixteenth century onward. For certain towns (e.g., London), summaries of these were published and were analyzed by John Graunt, one of the first demographers. John Rickman, the official in charge of the first census of England and Wales in 1801, arranged for abstracts of parish registers to be made. These were used by Rickman and by many subsequent demographers.

Beginning in 1952, French demographers began detailed studies of ecclesiastical records in selected parishes. By linking the names on the registers of baptisms, marriages, and funerals, they were able to reconstitute the histories of cohorts of families over the years. This method of family reconstitution has since been used in several European countries and in Quebec. The technique has proved extremely fruitful and, for many demographers, the term "historical demography" is restricted to this micro-demographic approach.

Estimates, by various scholars, of the trend in the size of the world population by continent were summarized by J. N. Biraben in 1979. Later estimates are available from the publications of the United Nations and international agencies such as the World Bank. Table 1 shows these estimates for the world as a whole, and, to reduce the effect of migration, for two continental aggregates: Europe (including Russia) plus the continents where people of European descent predominate (North America and Oceania); and the remaining continents. As well as the estimates of population size (in millions), Table 1 shows the annual growth rates, expressed as increase per thousand per year. The impact of these growth rates can be appreciated by relating them to the doubling time they imply. An annual growth rate of one per thousand would require 694 years to double the population. Rates of 10 or 20 per thousand have doubling times of 70 or 35 years respectively.

During the period from 500 to 900 C.E., there was very little growth in the world population, but between 900 and 1300 C.E. the population doubled, the growth rates being slightly higher in Europe than elsewhere. During the fourteenth century, there was a fall in population associated with the Black Death, a pandemic plague that spread from the Gobi desert to China, India, the Middle East, and Europe. This was followed by a period of restrained growth for three hundred years.

Beginning in the eighteenth century, the size of the world population entered a period of accelerated growth. At first the acceleration was more marked in the European population, reaching a peak growth rate of 10 per thousand per year in the second half of the nineteenth century. During the twentieth century, the growth rate among the European populations slackened and was overtaken by a rapid acceleration in the growth rate in other continents, which reached 21 per thousand per year in the last fifty years of the millennium. Between 1900 and 2000 C.E. the population of the world increased by 277 percent; the European

Table 1

component increased by 124 percent, and the remainder by 349 percent.

The recent micro-demographic technique of family reconstitution provides a more detailed analysis of the surge in the European population during the eighteenth century than is possible from the macro-demographic estimates in Table 1. Michael Flinn has collated the results of such studies in Belgium, England, France, Germany, Scandinavia, and Switzerland. In-depth analyses of the parish registers in England have been published by E. A. Wrigley and Roger Schofield. Table 2 is derived from these books and from that edited by Tommy Bengtsson and colleagues.

The size of a population that is closed to migration is the product of the number of live births per year and the average number of years lived (expectation of life at birth). In eighteenth-century Europe, less than 5 percent of live births were illegitimate, so it is reasonable to focus on the number of legitimate births. The latter is the product of the proportion of women who marry before menopause and the average number of live births per marriage. The first row of Table 2 suggests that the proportion of women marrying increased during the eighteenth century, though the data are available only from English parishes, and in proxy form—the proportion of those between forty and forty-five years of age of both sexes who were married. The second row of the table shows that the average number of live births per marriage remained high during the eighteenth century but fell slightly in the early nineteenth century. The third row shows that the expectation of life at birth increased considerably during the eighteenth century, a trend that continued into the nineteenth century.

The fourth column of Table 2 shows the percentage of increase of these statistics between the early eighteenth and early nineteenth centuries. The small changes in the proportion marrying (minus 9%) and the average number of live births per marriage (6%) are outweighed by the large increase in the expectation of life at birth (29%). This is consistent with the hypothesis that the spurt in the European population during the eighteenth century was due to a fall in mortality rather than an increase in fertility, though the question of the role of fertility is still a matter for debate. The reduction in the average number of live births per marriage over the century, despite the increase in the proportion marrying, can be explained by the increase in the average age at first marriage among women, shown in the fourth row of Table 2. Since a woman's fertility reduces with increasing age, even small increases in the average age at first marriage can reduce the average number of births. The last two rows of Table 2 show that most of the gain in expectation of life at birth was due an increase in the proportion of infants surviving

Table 2

long enough to marry. Very little was due to change in the expectation of life at age twenty-five. After the eighteenth century, death rates in Europe continued to fall, and in the nineteenth century the fertility changes seen in Table 2 accentuated, leading to a compensating fall in the birth rate.

Before the introduction of organized public health programs in the nineteenth century, high levels of mortality were caused by the correlated effects of war, famine, and pestilence. The precise manner in which mitigation of these factors led to the fall in mortality in the eighteenth century is still debated by historians, but the debate has been considerably enriched by the studies subsumed under the term historical demography.

(SEE ALSO: Bills of Mortality; Birthrate; Demography; History of Public Health; Mortality Rates; Population Pyramid)

Bibliography

Bengtsson, T.; Fridlizius, G.; and Ohlsen, R., eds. (1984). Pre-Industrial Population Change: The Mortality Decline and Short-Term Population Movements. Stockholm: Almqvist and Wiksell International.

Biraben, J. (1979). "Essai sur l'évolution du nombre des hommes." Population 1:13–24.

Flinn, M. W. (1981). The European Demographic System. Baltimore, MD: Johns Hopkins University Press.

Glass, D. V., and Eversley, D. E. C., eds. (1965). Population in History: Essays in Historical Demography. Chicago: Aldine.

Hollingsworth, T. H. (1969). Historical Demography. Ithaca, NY: Cornell University Press.

Livi-Bacci, M. (1992). A Concise History of World Population, trans. C. Ipsen. Cambridge, MA: Blackwell.

Walter, J., and Schofield, R., eds. (1989). Famine, Disease and the Social Order in Early Modern Society. Cambridge, MA: Cambridge University Press.

Wrigley, E. A., and Schofield, R. S., eds. (1981). The Population History of England, 1541–1871: A Reconstruction. London: Edward Arnold.

— GERRY B. HILL