This article approaches the study of pragmatic meaning in English modal verbs like can, may, and shall in early eighteenth-century English prose using the techniques of corpus linguistic analysis, politeness theory, and social network analysis. The study is based on a quantitative survey of modal expressions across registers in a corpus of fourteen early eighteenth-century authors, which yields relative frequencies of occurrence according to genre and to author. Together with the sociohistorical information provided by the strategic coalitions constructed to develop, nurture and maintain relationships between clients and literary and political patrons, this survey provides the context for a pragmatic study of politeness strategies. The subsequent qualitative examination of letters in the oeuvres of selected authors yields a rich picture of individual pragmatic variation. The study reveals that although the corpus as a whole exhibits trends for different usages in different genres, the letters exhibit a predominance of modal expressions that may be used to index the facework involved in building and maintaining relationships of patronage. Within this genre, modal choice is influenced by a writer's sense of the relationship with the patron as well as the degree of risk and cost involved in the communication.