Question: Ivanhoé is an 1826 pastiche opera in three acts with music by Gioachino Rossini, the  music was adapted, with the composer's permission, by the music-publisher Antonio Pacini from Rossini's operas, namely La gazza ladra, is a "melodramma" or opera semiseria in two acts by Gioachino Rossini, with a libretto by who?
Answer: Giovanni Gherardini