The Cerdanya valley in the eastern Pyrenees has a physical unity into
which a political frontier has been imposed to divide it. The social and
cultural repercussions of this Franco-Spanish border have created obstacles to
marriage which are not due to topography. Choice of month of marriage is under
cultural control and the study of seasonality in marriages recorded in the
registers of all the Cerdan parishes on both sides of the border demonstrated
differences over time and between French and Spanish sectors. It is suggested
that these changes demonstrate the process of distancing of the two
populations. Cluster and correspondence analysis showed progressive
differentiation of the seasonality patterns of the French and Spanish Cerdans despite the geographic unity of the valley. Sociocultural factors are presumed responsible.