Hajnal line

The Hajnal line links Saint Petersburg, Russia and Trieste, Italy. In 1965, John Hajnal discovered it divides Europe into two areas characterized by a different levels of nuptiality.

West of this line, the average age of women at first marriage was 24 or more, men 26, spouses were relatively close in age, and 10% or more of adults never married. East of the line, the mean age of both sexes at marriage was earlier, spousal age disparity was greater and marriage more nearly universal. Subsequent research has amply confirmed Hajnal's continental divide, and what has come to be known as the 'Western European marriage pattern', although historical demographers have also noted that there are significant variations within the region.

The Western European pattern of late and non-universal marriage restricted fertility massively, especially when it was coupled with very low levels of childbirth out of wedlock. Birth control took place by delaying marriage more than suppressing fertility within it. Women's life-phase from menarche to first birth was unusually long, averaging ten to twelve years.

The region's late marriage pattern has received considerable scholarly attention in part because it appears to be unique; it has not been found in any other part of the world prior to the Twentieth Century. The origins of the late marriage system are a matter of conjecture prior to the 16th Century when the demographic evidence from family reconstitution studies makes the prevalence of the pattern clear. Many historians have wondered whether this unique conjugal regime might explain, in part, why capitalism first took root in northwestern Europe, contributing to the region's relatively low mortality rates, hastening the fragmentation of the peasantry and the precocious formation of a mobile class of landless wage-earners, especially in Northwestern Europe. Others have highlighted the significance of the late marriage pattern for gender relations, for the relative strength of women's position within marriage, the centrality of widows in village land inheritance, and the vitality of women's community networks.