Meyerbeer’s opera, written four years before Rossini’s Semiramide, is based on an adaptation, probably done by Count Ludovico Piossasco Feys, of the libretto written by Pietro Metastasio in the far-off year of 1729, which had already been set to music several times by leading composers of the eighteenth century. Count Piossasco Feys worked skilfully and transformed the Metastasio tragedy, based on the classical alternation recitative - solo aria, into a more agile, modern structure, including a smaller number of arias, duets, trios and ensemble pieces. Meyerbeer’s opera was written for one of the most esteemed singers of the day, Carolina Bassi, a performer with a great vocal range that enabled her to give of her best both in contralto and in soprano roles. In the early part of the opera, where Semiramide dresses in men’s clothing, passing herself off as her son, Meyerbeer writes her part using a rather low register.

Composed for Venice in 1837, just a year-and-a-half after the fantastic success of Lucia di Lammermoor, Pia de' Tolomei "pleased altogether", in the composer's words. He revised it a couple of times thereafter and it was shown at various theaters as distant as Malta until 1855, after which it disappeared. It takes place in 13th-century Siena: Pia is married to Nello; his cousin Ghino loves her but she refuses his advances. Ghino angrily accuses Pia of adultery with an unknown man, who turns out to be Pia's brother, Rodrigo, and Nello imprisons her. Ghino eventually feels remorse and confesses his deception, but not soon enough to save Pia from being poisoned by Nello.

Mercadante had lived in Spain, where his operas had been popular and appreciated, and it was here that he had started to think about an opera based on a typically Iberian subject to win the appreciation of the local public: the story of the king of the Asturias Pelagio, who in 718 (or, according to other sources, in 722) defeated the Arabs in the battle of Covadonga. The story have left a strong mark on the composer, for almost thirty years later, in 1855, he entrusted the production of a libretto to Marco D’Arienzo, who had already worked with him writing. First performed at the San Carlo theatre in Naples on 13th February 1857, Pelagio is the last but one of the operas that Mercadante saw on stage but in chronological terms, however, this was his last one.