Count Volf Engelbert Auersperg, once a student of the Graz Jesuits, was also their greatest patron. The article describes the most important works of the Graz Jesuits held by the Volf Engelbert Auersperg library, as well as giving a brief depiction of the works of other Habsburg, Roman and German Jesuits. Fifteen year-old Volf was one of the Carniolans to revert to the Catholic faith, otherwise he would not have been permitted to study at Graz University where he first became acquainted with early modern science, and compiled a considerable personal collection of Graz Jesuit manuscripts and books, of which several are described for the first time in this article. When the German universities lost their standing because of the Thirty Years War, Volf continued his studies in Northern Italy. Here Volf was influenced by Italian and even Venetian culture, the effects of which were significant also at that time in Ljubljana and which tapered off later when German ascendancy prevailed. Volf introduced the opera, music, and the physics innovations of Galileo’s Tuscan and Kircher's Roman Jesuit circles to Ljubljana.