Tomaž Hren (1560-1630), the Bishop of Ljubljana, was the leading person in Carniola during the Anti Reformation period. His duty was to carry out ecclesiastical reform in the spirit of the Tridentine Council. He ordered the destruction of Protestant books, with the Pope's permission he preserved only the Dalmatin Bible; he was aware of the power of the vernacular language in the strengthening of religion. He worked to set up a printing house in Ljubljana. The texts in the Slovenian language that he approved were solely of a Catholic religious nature, and he edited and reviewed them himself. He financially supported many\nartists, especially musicians dealing with liturgical music. Hren’s choir books represent a selection of a diverse liturgical works that were popular in the Inner Austria - masses, magnifiers, litanies, psalms, hymns, Marian antiphons and short chants. Compositions in the Hren’s choir books were mostly created by Italians from Venice and other northern Italian regions. There are five\ndifferent writings in the books: three intertwine, indicating the existence of a workshop in Graz where the main writer Georg Kuglmann came from, while according the other two scripts it can be assumed that the compendium was not entirely transcribed in one place.