About this "The Simpsons" episode:

The Simpsons - Lisa the Iconoclast is the 16th episode of season 7 and number 144 overall in the series.
While doing research for an essay, Lisa finds a confession written by town founder Jebediah Springfield revealing that he was a murderous pirate named Hans Sprungfeld who tried to attack George Washington and never cared about the people of Springfield. Homer decides to help Lisa get the message out, but they are arrested by the town council. Lisa claims Sprungfeld had a silver tongue so the council decides to exhume Jebediah to prove Lisa wrong. It turns out that there is no silver tongue but Lisa later discovers that it had been stolen from the grave by Hollis Hurlbut, the local historian. The two rush to reveal the truth about Jebediah, but Lisa realizes that the myth had inspired the entire town and decides to keep it a secret.