Everything takes on symbolic meaning in “The Cask.” Every detail seems to stand for something else, or to be flashing an encoded, and no doubt gruesome, message that we are compelled to decipher. The Montresor family coat of arms really stands out, though, for several reasons.
First let’s break down the description. Picture a shield. On it is a picture of a giant gold “human foot” in “a field azure” – i.e., a blue field. The foot is “crush[ing]” a wild and crazy “serpent.” The serpent’s fangs are buried in the foot’s heel. Seems obvious, right? Fortunato is a snake in the grass, he bit Montresor, and Montresor’s big gold foot is coming crashing down on him as a result.
There’s that motto to go with it: “Nemo me impune lacessit.” A quick search of the Internet reveals that this means “no one attacks me with impunity” − and that it’s the motto of Scotland!
When we find this out, it becomes pretty obvious that the coat of arms is fabricated. It’s Montresor’s fantasy of what he wants to have happen, and yet another hint that Fortunato doesn’t get. But all that really tells us is what we already know: Montresor lies.
What’s really significant about the arms is the color “azure.” This is the only color explicitly mentioned that isn’t connected to death and darkness. It literally means “sky blue” and sky means freedom, especially when we contrast it with the claustrophobic, prison-like atmosphere of the catacomb.
This also speaks to the theme “Drugs and Alcohol.” We know that Poe often used his fiction to explore his addictions, one of which was the drug laudanum. Laudanum comes from poppies – often blue ones. The “field azure” on the arms could be a field of poppies. If so, it makes all that stuff about freedom seem ironic. If it represents addiction, it represents imprisonment, thus highlighting the story’s tension between freedom and confinement.