Cousin marriage in south-western England in the nineteenth century.

Knowledge of inbreeding levels in historical times is necessary to estimate the health consequences of past inbreeding, and to contextualize the current public debate about cousin marriage in Britain. This research aims to calculate the level of cousin marriage using the intensive technique of multi-source parish reconstitution and to determine whether village organization, religion and occupational class influenced the level of consanguineous marriage. A wide variety of documentary sources were used to create extensive pedigrees of spouses in over 800 marriages in the 19th century in the rural villages of Stourton and Kilmington. The closed village of Stourton had higher levels of inbreeding than the open village of Kilmington. Catholics had lower rates of 1st cousin marriage but higher rates of 2nd cousin marriage than Protestants. Farmers had higher levels of 1st cousin marriage than labourers. The levels of consanguinity in south-western Wiltshire in the 19th century were related to the economic structure of the villages and the religion and social class of the spouses.