29. It isn't only coloratura sopranos who have "mad scenes"; the great Marilyn Horne went wonderfully mad playing this title character in an opera by Vivaldi, who was also the subject of an opera by Handel.
From Quiz Operatic Madness
Answer:
Orlando
Vivaldi's "Orlando Furioso" is based on the epic poem by Ludovico Ariosto, which takes place during the Saracen invasion of France and features the evil sorceress Alcina, also the subject of an opera by Handel. Orlando, the legendary warrior nephew of the emperor Charlemagne, is consumed with love for the lovely Angelica. Angelica, however, falls for a young Saracen named Medoro; when Orlando finds their names engraved on a tree, jealousy drives him completely mad (hence the title "Furioso") and, among other things, he imagines that he is Orestes, the son of Agamemnon (see q.2). Eventually, however, he regains his wits, forgives Angelica and Medoro, and wishes them well. Marilyn Horne's facility at portraying "trouser roles", particularly of a military nature such as this one, has earned her the nickname "General Horne". She found a tailor-made vehicle in this role, which was originally written to be performed by a castrato.