Contextualisation is a ubiquitous feature of the work of philosophical and intellectual historians, and an adequate account is crucial to understanding the methodological underpinning and practices of historians of philosophy. Building on a proposal by Quentin Skinner, the authors develop an account of contextualisation in the history of philosophy in terms of pragmatics. Specifically, they draw on cognitive accounts of linguistic interpretation (relevance theory) to explain how contextualisation works in the history of philosophy: contextualisation involves speech acts best understood on the ‘ostensive-inferential’ theory of human communication. What makes contextualisation ‘historical’ on this approach is the fact that in order to infer to those elements of speaker’s context that are needed to interpret speakers’ meaning, historians of philosophy need to leverage historiographical techniques.