Around 1700 'Philadelphia', the idea of a cross-denominational covenant of the 'Children of God', advanced to a widespread ideal of German pietism. The idea was propagated above all by the followers of the English community of the 'Philadelphians'. Research has long suspected that the English Philadelphians had a significant influence on both radical Pietism and the Herrnhut dynasty (Moravian Church) as well as on broader social debates in the Old Empire. But what exactly were these influences? In the Gotha Research Library, there is a geographically arranged 'Catalogus amicorum in Germania', which served the Philadelphians as a starting point for their German mission, together with a volume of letters from this group. In addition, there are important holdings in other archives, which have also received little attention from scientists. Based on these sources, the project will reconstruct the early network of the Philadelphians between England and Germany and the social and cultural mediating role of their ideas. Particular attention will be paid to the role of language: Many German contemporaries saw the language of the Philadelphians - which was ultimately created through translations from English - as the Pietist language par excellence. However, it is still necessary to specify what linguistic and cultural contribution the group actually made. The project thus aims to investigate the emergence of the language of Pietism, which is perceived as a source of identity, using the example of the German Philadelphians and to examine the role translations played in the service of cultural transfer.