About the work
Il giuramento is a three-act opera by Saverio Mercadante to a libretto by Gaetano Rossi, who relocated his source, Victor Hugo's play Angelo, tyran de Padoue, from Padua to fourteenth-century Syracuse. It premiered at Teatro alla Scala in Milan on 11 March 1837.
Plot
Bianca, married against her will to Count Manfredo, secretly loves the knight Viscardo, long believed dead. Elaisa, a stranger once saved by Bianca's father, is at first consumed by jealousy but ultimately protects the couple: when Manfredo orders Bianca poisoned, Elaisa swaps the poison for a sleeping draught. Believing Elaisa responsible for Bianca's apparent death, Viscardo stabs her — recognising his victim only as she dies.
Cultural significance
Mercadante regarded Il giuramento as a turning point: it was the first opera premiered in Italy in which he denied the prima donna a closing showpiece aria, subordinating vocal display to continuous dramatic action. It became his greatest success and was staged across Europe in the following years, including Vienna, London and Paris.