Deception and Appearance vs. Reality

Characters frequently disguise their true identities or intentions—Matilda poses as a novice, Theodore as a beggar, and Ambrosio as a holy man—revealing the theme that outward appearances often mask hidden, often sinister, realities.

Lorenzo's dream and the mysterious stranger's actions underscore the theme of hidden truths and deceptive appearances.

The Marquis conceals his true identity as Alphonso d'Alvarada, and Donna Rodolpha's false account misrepresents his actions, highlighting the theme of deception.

Raymond's friendly attentions to Donna Rodolpha are misinterpreted as romantic love, leading to a dangerous misunderstanding.

The prioress feigns grief and claims Agnes died, while Lorenzo sees through her hypocrisy.