This paper explores the social history of the modal auxiliary may between 1400-1800. The material used comes from the Corpora of Early English Correspondence. The development of may on the lexical level is tracked with regard to the social variables of gender, rank, social mobility, education and register variation. The social embedding of the rising epistemic meaning is then described with the help of a socially stratified sample of instances. The results show that the use of may is connected to the expression and negotiation of relative power and intimacy between correspondents. Furthermore, the rise of epistemic may originated with educated men, and spread gradually to other language users.