A central organising principle of any curriculum is the substantive concepts that underpin it. They provide a secure structure and enable students to develop deep understanding through multiple encounters with essential abstract ideas that are given concrete form in different historical contexts. Identifying the different levels or tiers to which different kinds of substantive concept belong provided a powerful tool for Gareth Lennon and his colleagues as they sought to redesign their curriculum. In this article, Lennon summarises the approach that his department adopted, drawing a careful distinction between foundational concepts, supporting concepts and concrete examples. He also explains how they have tested the effectiveness of their curriculum’s design and construction through their mid- and end-of-year assessments, ensuring that the curriculum genuinely serves to strengthen and progressively enrich students’ knowledge and understanding of the past...