The book "Letters of a Portuguese Nun" is a literary masterpiece that was published anonymously in 1669 in Paris under the authorship of Gabriel Joseph de Laverge, the elder de Guilleragh. It is a translation of idealized love letters to a young Portuguese nun, Mariana Alcofratrado, transmitted through a French officer who is in love with her. In these letters, she talks about her unreasonable love, suffering and faith in eternal love. The book impresses with its emotionality, mysticism and deep sense of loss, creating a unique image of a soul in love seeking forgiveness for love. The letters touched the hearts of not only the hero, but also millions of readers around the world, prompting reflection on the essence of love and devotion.