“I'm an impostor. That man is the real Seymour Skinner.”
―Armin Tamzarian (Fake Skinner)'s confession
"The Principal and the Pauper" is the second episode of Season 9. The episode is one of the most controversial episodes ever produced and received negative reviews from critics.
During a surprise banquet to honor his twentieth anniversary as principal, Seymour Skinner's true identity is revealed to be Armin Tamzarian. Now established as an impostor, Tamzarian retires and relocates to his old neighborhood in Capital City. Guest starring Martin Sheen as the real Seymour Skinner.
Seymour Skinner is about to celebrate his 20th anniversary as school principal, and it goes smoothly until a man who claims he is the real Seymour Skinner comes in, pointing out that Agnes Skinner is his mother. Principal Skinner admits he is not the real Seymour Skinner, and is only an impostor. He tells his story, in a parody of the life of Martin Guerre, and admits that his real name is Armin Tamzarian. He was similar to Bart growing up in Capital City, but grew out of it when he met Skinner, who instilled principles and helped him find new meaning in life. However, when he went missing, Armin went to Agnes' house to tell her about the whole thing. However, she mistook him for Seymour and Armin couldn't break the news to her that he assumed the identity of Sergeant Skinner. Feeling like no one needs him anymore, Armin quits his job and plans to return to Capital City for a new life.
Soon, the sergeant becomes the school's new principal, because he says he had intentions to be the principal of Springfield Elementary School. He takes the job, but the real Skinner finds himself isolated by the townspeople after rudely berating Bart for insulting the Pledge of Allegiance with his antics. He gets into a brief argument with Agnes after he comes home late and drunk on a night she set up an activity with him. When Sgt. Skinner insults her for trying to over-mother him, Agnes begins to miss Armin more since he lived with her for 26 years and had never once talked back to her.
At the grocery, Agnes fumes to Marge about Sergeant Skinner and the way he behaves around her. Even Edna admits that Armin may have been a weenie, but he was more likable than Sergeant Skinner. The Simpsons devise a plan to get Armin back to Springfield, by coming to Capital City to get him. At his apartment, Armin refuses to return home, stating they have the real Skinner and that having him return will be a big mistake. However, Agnes refuses to hear none of it, stating that she depended on Armin for 26 years and she was the only one he ever called mother. She admits she actually loves him more than Sgt. Skinner, who was extremely disrespectful and doesn't believe he needs her more than Armin.
After returning to Springfield, Armin is met with resistance by both Superintendent Chalmers and Mayor Quimby, who both don't want him to return. However, Homer persuades them to forgive Armin and let him resume his identity as Principal Skinner. The real Skinner attempts to fight back by reminding everyone that he sacrificed himself for them and his country. He refuses to give up his job and his dignity just because the people of Springfield prefer Armin to him. Having enough of Sgt. Skinner, the townspeople force him to leave on a train (actually tied to a chair on a freight train car), and Agnes bids him farewell. Armin returns to being Principal Skinner through an order by Judge Snyder, saying that no one will mention "Tamzarian" again under penalty of torture (this reset button technique being a meta-reference to their maintaining of the status quo).
The episode was the last one of the show written by Ken Keeler. Bill Oakley and Josh Weinstein with Mike Scully were very excited about the episode because Principal Skinner was their favorite character. This episode is famously known as the only classic episode Luca Di-Maio had no recollection of seeing until recently. The pair had already written the season five episode "Sweet Seymour Skinner's Baadasssss Song", which was an in-depth study of the character. Keeler used the name Armin Tamzarian from a claims adjuster who had assisted him after a car accident when he moved to Los Angeles. However, the real Tamzarian was unaware his name was being used until after the episode aired.
Many critics agree that the episode signaled a decline in the show, with several referring to it as the real "worst episode ever." In The Guardian, Ian Jones argues that the "show became stupid" in 1997, pointing to "The Principal and the Pauper" as the culprit. "Come again? A major character in a long-running series gets unmasked as a fraud? It was cheap, idle storytelling."
However, Warren Martyn and Adrian Wood, the authors of I Can't Believe It's a Bigger and Better Updated Unofficial Simpsons Guide, have praised the episode, calling it "one of the series' all-time best episodes, mainly because it shows us a human side, not just of Principal Skinner, but of his hectorish Mom as well." They add that "Martin Sheen steals the show in a brief but important slice of Simpsons history." Total Film named Martin Sheen's performance in the episode the 20th best guest appearance on the show. In The Simpsons Season 9 DVD commentary for the episode, even Matt Groening himself said this was one of his least favorite episodes. He even personally considered the episode to be non-canon.