The purpose of this article is to explore the reach of mnemonics practices and the idea of mental images in illuminated manuscripts, specifically in five illuminated manuscripts of the Psychomachia that are dated between the 9th and 10th century. During the Middle Ages, mnemonics were a key point for learning. Many Literature scholars have studied the relationship between mnemonics and virtues and vices, and how mental images of these allegories aided the memory. Within the monastic culture, the mental images of the virtues and vices helped monks to learn and memorize the moral teachings of the Church. It suggests that the illuminations in these five manuscripts were meant as mnemonics devices for the monks, especially those that could not read at all.