What did Fortunato do to Montresor?
The story does not tell us exactly. Montresor begins by claiming many injuries and a final insult, but he does not describe a specific offense in enough detail for a reader to judge it independently. That absence is one of the tale’s most consequential choices.
Fortunato’s conduct during the journey can help us understand the relationship as Montresor presents it: pride, condescension, misunderstanding, and competing claims to status are all available to examine. But those scenes do not retroactively establish the precise insult announced at the opening. An interpretation must not quietly turn a possible motive into a fact supplied by the text.
The uncertainty shifts attention toward the storyteller. Why does he expect his listener to accept the grievance without particulars? What does his elaborate account reveal about the meaning of revenge to him? The tale gives readers material for those questions while withholding a neutral history of the dispute. A summary that confidently names the original offense would add something Poe’s narrative leaves unsaid. Preserving that gap is more faithful than solving it through invention.
Sources and further reading
Editorial answer from Ask Poe. Interpretive readings are distinguished from documented publication facts. Check the linked texts and editions.