This paper examines the historical origins of violence against women, in contrast to earlier literature, which focused only on short-term determinants. It analyses the relation-ship between traditional family patterns (stem versus nuclear) and intimate-partner violence (IPV). Stem families are those in which one child stays in the parental household with spouse and children, so that at least two generations live together. I model the behavior of a traditional peasant family and show how coresidence with a mother-in-law increases a wife’s contribution to farmwork. This increased contribution is shown to potentially decrease the level of violence, since the wife’s reduced productivity acts as a deterrent. In my empirical analysis I use Spanish data, as Spain offers IPV measures of the highest quality as well as a persistent geographical distribution of family types. Results show that areas where stem families were socially predominant in the past currently have a lower IPV rate. I control for a large number of contemporary, historical, and geographical variables. To address causality, I use the stages and differences in the Christian conquest of the Iberian Peninsula (722-1492) as an instrument for the different family types. My instrumental variable results are consistent with my original findings.