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 operas.