Given the task definition and input, reply with output. In this task, you're given passages that contain mentions of names of people, places, or things. Some of these mentions refer to the same person, place, or thing. Your job is to write questions that evaluate one's understanding of such references. Good questions are expected to link pronouns (she, her, him, his, their, etc.) or other mentions to people, places, or things to which they may refer. Do not ask questions that can be answered correctly without understanding the paragraph or having multiple answers. Avoid questions that do not link phrases referring to the same entity. For each of your questions, the answer should be one or more phrases in the paragraph, and it should be unambiguous.

Passage: "Climbing over rocky mountain" is the best known piece from Thespis, as it was transplanted in 1879 into one of Gilbert and Sullivan's most successful operas, The Pirates of Penzance. In 1902, Gilbert told a correspondent that this had happened accidentally. He and Sullivan had arrived in New York to produce the new opera, but the composer discovered that he had left his sketches behind in England. Fortunately, the entrance chorus from Thespis fitted the situation almost exactly, so it was substituted instead.Several scholars have doubted that explanation. In Sullivan's autograph score for the later work, the first part of "Climbing over rocky mountain" is actually taken from a Thespis copyist score, with the Thespis words cancelled and the new words written in, which raises the question of why Sullivan had a Thespis score to hand, if not for that purpose.Some suggest that other music from Thespis could have been used in Pirates. Goldberg suggests that "It is reasonable to believe that Sullivan made generous use of his Thespis music in other operettas: perhaps owing to the circumstances under which The Pirates of Penzance was written, it contains more than one unacknowledged borrowing from the unlucky firstling of the lucky pair." Reginald Allen says that "it seems certain" from its "rhythmic structure" that part of the Act I finale of Thespis, "Here's a pretty tale for future Iliads and Odysseys" became the original Act II finale in Pirates, "At length we are provided with unusual felicity", which was later deleted. Tillett and Spencer propose that most of Act I of Pirates was taken from Thespis. However, there is only circumstantial evidence for these suggestions. Except for "Climbing over rocky mountain", neither author admitted to borrowing from Thespis for later works.
What was transplanted in 1879 into one of Gilbert and Sullivan's most successful operas?