How does Poe explore the theme of disguise?

Poe explores the theme of disguise in this story, both in practical and psychological terms. For example, disguise is a critical component in Montresor's ability to carry out his revenge plot. The story is set during Carnival, just before Lent, during which everyone who is celebrating wears a costume to disguise his or her identity. Montresor uses his disguise, a mask and black cloak (much like an executioner) to ensure that he is not identified as having been with Fortunato. Fortunato is himself costumed as a jester or fool, symbolic of his character. In addition, the catacombs, part of the gothic framework of the story, also provide a crucial part of the disguise—they are hidden underneath Montresor's palazzo and descend into the earth where no one goes on a regular basis (except to the upper levels where wine is stored). From a psychological standpoint, Montresor very successfully disguises himself and his intentions from Fortunato and the outside world when he poses as Fortunato's true friend, and one can argue that the "insult" itself is the most important disguised element of all.