We analyze the emergence of the first socioeconomic institution in history limiting fertility: west of a line from St. Petersburg to Trieste, the European Marriage Pattern (EMP) reduced childbirths by approximately one-third between the fourteenth and eighteenth century. To explain the rise of EMP we build a two-sector model of agricultural production—grain and livestock. Women have a comparative advantage in animal husbandry. After the Black Death in 1348–1350, land abundance triggered a shift toward the pastoral sector. This improved female employment prospects, leading to later marriages. Using detailed data from England, we provide strong evidence for our mechanism.