This study raises the question of why the French secondary school history curricula introduced in the late 2000s prescribed more extensive coverage of plural histories than did secondary school history curricula for English schools introduced in the same time period. Both countries share similar societal diversity. To explain the variation in curricula content, I argue that one needs to supplement a focus on ideas with an institutionalist perspective. England and France have different institutional frameworks for curricula creation, with roots in the nineteenth century, when mass education began. The research shows that these unique national education institutional legacies are significant, and that institutional contexts matter in the diffusion of ideas.