El juramento (Spanish for The Oath) is a 3-act zarzuela by
Joaquín Gaztambide for libretto by Luis de Olona. Its central character (the Marquis) is taken from a French operetta La Rose de Peronne by Eugène Scribe and
Adolphe Adam (1840), but the new work is entirely original. It was first staged on 20 December 1858 at the Teatro de la Zarzuela. It is thought to be among Gaztambide's best compositions and one of the most important scores in the history of zarzuela. The first modern performance took place in 2000 in Madrid Teatro de la Zarzuela.
