On the basis of direct and indirect evidence, three main types of musical repertoire in the early-seventeenth-century Slovenian lands can be established that directly relate to the Counter-Reformation: plainchant, sacred song in the vernacular, and contemporary polyphonic music. The textual emphasis of the preserved musical pieces above all helped to shape a distinctly Counter-Reformation religious identity: contemporary polyphonic compositions, above all Litanies and Marian antiphons, with the emphasis of the dogma of sanctoral intercession; the acclamations Christus vincit with the stating of the pope Clemens VIII’s religious integrity; and responsory Sedil ie k’misi with accentuation of the transubstantiation. Although the vernacular songs heard in Corpus Christi processions are lost to us, they were probably characteristic of the Catholic soundscape and also must have attracted the attention of the listeners and confronted them with the confessional challenge directly. With the campaign of reform and propaganda, promoted principally by the bishop Hren, the successful progress of Catholic reform in the Slovenian lands at the beginning of the seventeenth century stabilised the situation in many musical institutions.