Una vieja (Spanish: An Old Lady)[1][2] is a one-act zarzuela by Joaquín Gaztambide for libretto (in verse) by Francisco Camprodón.
It is based on a French opéra comique La vieille by Eugène Scribe and François-Joseph Fétis (1826).
A beautiful Mexican girl, Adela, a widow of an old rich patriot, wanted to get back from Texas to Mexico.
León tells her that Conrado is in love with a girl from a portrait, which was drawn once by him from a photo, but they never knew who was the beauty depicted on it.
Adele's butler Pancho enters with bad news: a decree of the rebellious government orders to send all the captives to Texas.
Everybody is confused by such a sudden disaster, and Conrado follows the old lady to her room in order to think out a solution and avoid him being imprisoned.
The false old lady shows for a moment her real appearance to the captain, who admits with amazement that she is the girl from the portrait he loves.
It is interrupted by a slower episode (Menos in D major, actually a tune from the Rondó final), but the music soon gets back to the principal theme and proceeds to a coda.