Abstract Antoni Szandlerowski, „Confiteor”, expression, and epistolography The aim of the article is to highlight different forms of expression in ''Confiteor" by Antoni Szandlerowski (1878-1911). The work was published after the author's death in 1912. It contains the letters Szandlerowski sent to his beloved, Helena Beatus. Within it, he uses a wide array literary expression forms developed and used during the period of Młoda Polska; ''Confiteor" contains sublime emotional confessions and shows how fragile and even neurotic the represented love was. In his letters, Szandlerowski uses many exclamations and emphasizes his recognition of Beatus' virtues of spirit. The author is interested in symbolism and is strongly influenced by Near East mythology, ancient Greek culture, and by the early works of gnostic authors interpreting the Bible, let alone romantic poetry. He places a strong emphasis on the connection between him and Beatus and on how hard and complicated their love is.