This article reviews a century of US data on the impact of learning Latin and explores to what extent the collected findings demonstrate that Latin can play a role in improving pupils' educational attainments, particularly in first language (L1), modern foreign language (MFL) and cognitive development. Contextualising these data allows us to explore their aims, findings and shortcomings. We argue that, while the collated data do provide significant evidence for the beneficial impact of learning Latin on the L1 development of English native speakers, evidence for an impact on MFL and cognitive development is less substantial. It is thus important to acknowledge that these existing data should be interpreted with caution, as a meaningful starting point for new research questions based on modern methodologies.