The Library of the University of Wrocław preserves in its collection of early printed books the only surviving copy of the thesis of Maciej Ambroski (1600–1646), who later became a pastor of the congregation of the Unity of the Brethren in Żychlin. The book was published in 1622 and was the basis for the defence of the thesis written under the supervision of Georg Vechner (1590–1646) as well as Ambroski’s graduation from the academic gymnasium in Beuthen (Bytom Odrzański). The print contains an exegesis of Psalm XV (XIV) based on the Hebrew text with references to earlier translations and commentaries. The language of the book is Latin. At the end of the publication, the author attached his own attempts to paraphrase the text of the Hebrew psalm in Greek and Latin. Until recently thought to be missing, the print of Ambroski’s thesis is a testimony to the high level of education in Beuthen’s gymnasium Schönaichianum Carolatheum and the ambitious challenges undertaken by both the teaching staff of this school and their pupils.