In England before the Norman Conquest letters were written in both English and Latin, while in the Middle English period the medium of letter writing was Latin and French up to the end of the fourteenth century (Häcker 2011). Around 1400 French was replaced by English in all letters, except for communication involving the clergy, in which Latin continued to be used. This raises the question of how far French and Latin epistolatory traditions influenced English letter writing, in particular whether and to what extent English letter formulae are loan translations. To answer these questions a database of letters written in England in both Middle English and French was investigated. The analysis shows that letters contain a high number of formulae and that these correspond closely in English and French letters; in other words, the English formulae are calques of French ones. The evidence regarding the availability and content of letter writing manuals suggests the following scenario for the acquisition of letter writing formulae. It appears that both French and Latin letter composition was taught by tutors with the help of manuals, while in the case of English, it is likely that after a period of ad hoc translations by bilinguals (most likely tutors), the formulae became conventionalized and spread quickly. The competent use of the formulae by women indicates that formulae were also acquired via oral input outside the classroom.