The book of Latin stylistics Syntaxis ornata seu de tribus Latinae linguae virtutibus (1754) deals with the three virtues of Latin — purity, refinement and richness. The attention is focused on the issues of word and sentence purity on the background of the vernacular languages of Hungary in the 18th century. The author emphasizes how to avoid lexical and syntactical barbarisms and solecisms. This paper presents the most frequent mistakes made in Latin bases on the extensive lists in the book, which also allow the investigation of the analogies and differences between classical and neo-Latin syntactic structures. Principally, these occur in the predominant use of the conjunction quod instead of ut and of infinitive forms. The grammar book is also significant from the perspective of modern philology, as it also observes the progress and reciprocal influence of the domestic — German, Hungarian and Slovak — vocabularies.