“Then it occurred to me that as I was not well acquainted with the history of the drama [and] it might be well for me to make sure that this idea of mine was really new before I went further.” -Mark Twain
In the Autobiography of Mark Twain, Volume 2: The Complete and Authoritative Edition, Twain recounts the time when he came up with an idea for what he thought was a new play.
He said, “One day a splendid inspiration burst in my head and scattered my brains all over the farm…” He continued, “That wonderful inspiration of mine was what seemed to me to be the most novel and striking basic idea for a play that had ever been imagined.”
He then says that “I was going to write that play at once, and astonish the world with it; and I did, indeed, begin upon the work immediately.”
But then he realized that he should investigate whether, in fact, this idea for the play was new. He said, “Then it occurred to me that as I was not well acquainted with the history of the drama [and] it might be well for me to make sure that this idea of mine was really new before I went further.”
Twain wrote Hammond Trumbull, a person knowledgable in plays, to ask whether Trumbull had ever heard of Twain’s idea used on stage.
The response came back from Trumbull and:
It covered several great pages of foolscap written in Trumbull’s small and beautiful hand, and the pages consisted merely of a list of titles of plays in which that new idea of mine had been used, in about sixty-seven countries. I do not remember how many thousand plays were mentioned in the list. I only remember that he hadn’t written down all the titles, but had only furnished enough for a sample. And I also remember that the earliest play in the invoice was a Chinese one and was upwards of twenty-five hundred years ago.
Turns out the idea was old and well known.
Whether the idea is for a play, for a new invention, or other creative work, you may want to search to see whether the idea is, in fact, new.