Of Longhi's portrayal of herself as the aristocratic, cultured Saint Catherine of Alexandria, Irene Graziani writes that "when she exhibits an image of herself, Barbara, too, is presented according to the model of the virtuous, elegant and erudite woman, revisiting the themes which Lavinia [Fontana] had developed several years earlier in Bologna, according to a repertoire tied to late Mannerism". It has been suggested that Longhi may have presented her self-portrait as the devotional image of a saint in order to avoid the appearance of indulging in the sin of vanity. Originally commissioned for the monastery of Sant'Apollinare in Classe, the painting was acquired by the Museo d'Arte della Città di Ravenna in 1829, and underwent a restoration in 1980. Several other of her depictions of Catherine of Alexandria exist. Most of Longhi's paintings are unsigned, but on one she included the initials "B.L.F.", standing for "Barbara Longhi fecit" ("made by Barbara Longhi") and on another, "B.L.P.", for "Barbara Longhi pinxit" ("painted by Barbara Longhi"). As almost all of her work was unsigned, it is unknown how many paintings she created or are still in existence. Only about fifteen are definitively attributed to her. Of those, about twelve are paintings of the Virgin and Child; such paintings were very popular during the Counter-Reformation. It is thought that some of her works may be erroneously attributed to her father. Among Longhi's paintings which do not depict the Madonna is "Judith with the Head of Holofernes" (ca. 1570–75). This subject was also painted by other female artists including Fede Galizia, Elisabetta Sirani and Artemisia Gentileschi. Longhi's version differs greatly from two versions painted by Gentileschi in that it does not depict the violent act; instead, her Judith appears to seek forgiveness as she looks heavenward. This is consistent with Counter-Reformation ideas about willingness to admit guilt, and believing in absolution for the penitent. The simplicity of composition and subtle colour palette used in her paintings also reflect the doctrines of the Counter-Reformation. Her relatively small works, as opposed to the large altarpieces created by her father, are indicative of their intended emphasis on devotional thoughts. She sought to evoke empathy in the viewer with her subjects.