The Measure of Multitude: Population in Medieval Thought (review)

The Measure of Multitude: Population in Medieval Thought. By Peter Biller. (New York: Oxford University Press. 2000. Pp. xxi, 476. $55.00.)

How did medieval people, and the intellectual elite in particular, think about world population and the bundle of topics that we nowadays call demography—if and when they thought about these matters at all? Did they worry about optimum population size? If so, what did they do, or think they ought to do, to achieve it? How did practical experience with the world outside of Europe—crusades, missionary work, commercial contacts with non-Christians, and expeditions to the Far East, for example—affect notions about population that scholars encountered in the learned literature that they studied? These are the central questions that Peter Biller poses and seeks to answer in his wide-ranging and erudite monograph.

Christian beliefs and values played a key role in medieval speculations about marriage, reproduction, and population, and Biller accordingly devotes the first and lengthiest section of his book (chapters 2-8) to an investigation both of religious teachings about his topic and of the consequences of those teachings, so far as they can be discovered, on the actions of the Christian faithful. A second, much shorter, section of the book (chapter 9) looks at medieval geographical texts, as well as accounts of journeys outside of Western Europe, to the Holy Land and to Asia. In the following section (chapters 10-13) Biller explores treatments of demography in medieval translations from Greek and Arabic of works that deal with natural philosophy and medicine. He devotes no less than three chapters to the medieval reception of Aristotle's Politics, which he finds exceptionally important in this context. A concluding chapter focuses on demographic ideas current in a single city at one specific point in time, namely, Florence around the year 1300. Here Biller is particularly concerned with Dante's observations about population levels, as well as with the physical traces of the city's growth, as evidenced by the large-scale expansion of its walls at about this time.

Biller has drawn upon a vast array of sources in preparing his book. In its first section, where he devotes no less than three chapters to the theory and practice of contraception and abortion, he covers ground previously explored by John Noonan (1966) and John Riddle (1992 and 1997), among others, but also takes into account a considerable range of additional evidence. He draws much of this from William of Auvergne's treatise on the sacrament of marriage and from pastoral manuals, notably William of Pagula's Oculus sacerdotis and Speculum prelatorum ac religiosorum. Wolfgang Müller's admirable study of the criminalization of abortion (2000) might have added important nuances to his treatment of the canon law on abortion, but that work no doubt appeared after Biller's book had gone to press.

Biller makes some intriguing observations about medieval life expectancy, but he apparently overlooked one important area where this was crucial, namely, the pricing of life annuities. These instruments were in frequent use throughout western Europe from the thirteenth century onwards as a means of securing immediate cash against the hazard of a future liability. Monasteries often raised money this way, and medieval lawyers, civilian and canonist, dealt with the topic in considerable detail, as does an important modern study by Werner Ogris (1961), as well as a 1989 dissertation by Ronald Necoechea (University of California at Los Angeles).

That said, Biller's volume is a valuable and original contribution to a facet of medieval life and thought that has previously received scant attention from historians.