Church hymns in German did not gain much attention from linguists and were typically studied by theologians or musicologists. The project is related to the study of the genesis of the church hymn genre from the philological viewpoint. The authors dwell on the history of German liturgical tradition and present the developed corpus of liturgical texts in German. The aim of the study is to correlate thematically significant lexical items with the matrix of fundamental theological ideologemes. For this task, the authors compared frequency lists extracted from the corpus with the ones from the Gutenberg corpus evaluating them the values of keyness score. Further work involved selecting theologically significant concepts (ideologemes) and subsequent annotation of the identified lexical units by experts. The results include such important thematic lexis as Gott “God”, Mensch “Human”, and Engel und Heilige “Angel and Saints”. The emergence of Gott “God” as the central ideologeme indicates that the Catholic Church preserves the ideals of the Middle Ages. The peripheral position of ideologemes such as Heilige/Engel—Kirche—Maria “Saints/Angel—Church—Mary” can be also seen in contrast to the Mensch “Human” ideologeme that goes back to the Reformation.