The present paper deals with the correspondence of Count Johann Mailáth, a supranational go-between in the first half of the 19th century. The essay is a stocktaking of Mailáth's letters, they are collected in the Austrian National Library and the Vienna City Library. The author of the article would like to show that 1) Count Mailáth can be seen as a multiple “Grenzgänger” between communication spaces, languages and genres and 2) that the analysis of his multilingual and multiethnic network can determine several turning points in his writing career. The aim of the contribution is to supplement the previously known biography of the author and to define epochal boundaries in his oeuvre.