In the late eighteenth century, the distance between the changing norms and values and the unchanging material conditions of priests’ everyday lives grew rapidly. The aim of this article is to explore and understand the life and work of the bishop of Livonia, Józef Kazimierz Kossakowski. He was the author of Ksiądz pleban [The Parson], one of the most acknowledged parenetic books promoting new social obligations of priests, however his actions were far from the ideals he promoted. His case is especially interesting because he also wrote a diary describing his life from the childhood to becoming a bishop.