Setting out to teach Magna Carta to the full attainment range in Year 7, Mark King decided to choose a question that reflected real scholarly debates and also to ensure that pupils held enough knowledge in long-term memory to be able to think about that question meaningfully. As he gradually prepared his pupils to produce their own causation arguments in response to that question, King was startled by the beneficial effects of knowledge. This led him to raise questions about the relative value of investment in conventional essay scaffolding "vis-à-vis" investment in secure knowledge.