St Jerome and St Catherine of Alexandria (1480–1490) by Anonymous - Public Domain Catholic Painting

Jerome and Catherine sit on a grass-covered bench before some rose bushes. The two saints can be identified by their attributes: Jerome with the lion, and Catherine with the sword and the broken wheel. Catherine was the daughter of a king and served as a role model for wealthy courtly ladies. The costly heart-shaped book she holds probably contains love songs. Source

Saint Catherine is wearing a blue dress with red sleeves. Blue represents heavenly grace and red can represent martyrdom. Catherine was a virgin and martyr, so these colors are very appropriate. Saint Jerome, usually clothed in torn robes or sack cloth is—surprisingly—dressed in pristine red and white robes. Jerome was not a martyr, so the red in his garment likely represent power from God, and the white represents his purity. Jerome spent the end of his life working from a cave near Bethlehem, and so in that sense, he was purifying himself from worldly worries. This image was likely a portrait of two patrons who were given the attributes of these saints.