The 126 letters and 45 supplements assembled here represent the correspondence engaged in by the president of the Fruchtbringende Gesellschaft in 1637/1638. Those years were marked by rivalry among the national languages of Europe, a situation reflected not only by occasional literature and translation work in German, but also by bible literature, systematic linguistic research, the cultivation of epistolary style, and not least academic/scientific prose. This is closely connected to the membership structure of the Gesellschaft. The first and largest German academy brought together hundreds of intellectuals from all over Europe. Its declared intention was to make the German vernacular a vehicle for political and denominational communication, as well as for Christian and moral renewal.