Some great historical changes can be succinctly described by a few numbers. In 1650, the population of England was 5.2 million. In 1750 it was 5.7 million. In 1850 it was 16.7 million. Population increased in most other European countries as well, though not as rapidly. The sheer growth in the number of people did as much to change society and daily life in Europe as the Industrial and French revolutions and their aftermaths. Modem population growth has been the subject of a huge literature ever since 1798, when the Reverend Thomas Robert Malthus wrote his famous pamphlet. Many of Malthus's insights and recommendations were hotly disputed in his time. And although historical demographers today have a far larger body of information at their disposal, the dispute continues unabated. Still, historical demography has arrived at some points of consensus. One is that most of the growth of English population in the century before 1850 was caused by a rise in the birth rate, not a fall in the death rate; another, that the rise in the birth rate was due mainly to a rise in the propensity to marry, which started in the middle of the eighteenth century. A third is that before the eighteenth century England's population had been held in check mostly by what Malthus called the preventive check-through low nuptiality. Wars, epidemics, famines, and other factors on the mortality side of the equation were of secondary importance in the long term. Thus the changes in marriage patterns after 1750 led to a collapse of the Malthusian equilibrium and the consequent growth of population. How and why this change in nuptiality took place is far less clear. It is particularly odd in view of the very different experiences across Europe. In France, for instance, the female age at first marriage and the proportion never married do not start dropping until the 1820s. In Scandinavia, mortality decline played a much greater role than in England. The historical conundrum, as E. A. Wrigley has called it, that now demands resolution consists of two related questions: Why did English nuptiality rates rise so suddenly, and why was no other mechanism to regulate population size activated?