While weighing up the relative merits of the competing narratives of the Battle of Hastings that his department might present to Year 7, Matthew Stanford began to consider how the causal models that teachers introduce influence the causal arguments that students later go on to write. In this article, Stanford shows how such realisations informed his department's longer-term curricular planning. The department began to plan for pupils to understand and use increasingly complex causal models over the course of Key Stage 3.