• George Frideric Handel. Opera in three acts. 1723.
• Libretto adapted by Nicola Francesco Haym from Teofane (Theophanes) by Stefano Benedetti Pallavicino.
• First performance at the King’s Theatre, London, on 12th January 1723.

Otto, King of Germany, is travelling to Rome to marry Theophanes, Princess of the Eastern Roman Empire. Gismonda, widow of the usurper Berengar, and her son Adalberto make use of a delay in Otto's arrival, caused by conflict with and capture of Emireno, by letting Adalberto impersonate Otto. The resulting political and marital complications, increased by the participation of Otto's cousin Matilda, who is betrothed to Adalberto, are solved when Otto regains his bride and his position, with his prisoner Emireno revealed as Teofane's brother and rightful ruler of the Eastern Empire. Adalberto is forgiven, Gismonda satisfied and all ends well.

The gavotte from the overture enjoyed contemporary popularity, as did Gismonda's La speranza è giunta (Hope is with us) and Vieni, o figlio (Come, my son). Ottone's own arias include the despairing Tanti affanni (Such troubles).