In The Monk, cowls (loose hoods or hooded robes worn by monks) symbolize the unreliability of physical appearance to reflect inner truths. In particular, they represent religious hypocrisy. In the novel, two notably deceptive characters who wear cowls are Matilda and Ambrosio. Matilda makes her first appearance as a novice monk named Rosario, a disguise she puts on to try to get closer to her mentor, Ambrosio, whom she eventually admits she is in love with (at end of the novel, however, it’s revealed that this is a lie—in fact, Matilda was a demon whom Lucifer sent to try to tempt Ambrosio). Matilda wraps her cowl around her face to conceal her feminine facial features and avert Ambrosio’s suspicions. Later, Ambrosio will use the same method to conceal his own identity when he breaks his vow to never leave the monastery in order to visit Elvira’s apartment in town.
While Ambrosio’s and Matilda’s cowls hide their identities and thus demonstrate how looks can be deceiving in general, there is another layer of symbolism in the fact that these two characters are using a religious garment to conceal their true selves. Matilda, for instance uses her cowl to appear as a gentle and devout young monk rather than a sensual young woman (and, ultimately, a demon). Ambrosio, meanwhile, uses his cowl to hide the fact that he is breaking his religious vows, an action that goes against the public’s vision of him as the epitome of self-discipline and religious devotion. Furthermore, the fact that he is using a religious garment to prevent the public from learning that he has broken his vows suggests that his virtue is only superficial and surface-level: although he appears devout to his followers and has no qualms about judging them harshly for their sins, in reality, he is just as flawed and subject to baser human urges as anyone else.