Tancrède is a 1702 tragédie en musique (a French opera in the lyric tragedy tradition) in a prologue and five acts by composer André Campra and librettist Antoine Danchet, based on Gerusalemme liberata by Torquato Tasso.
It is famous for having the alleged first contralto role in French opera.
The role was written for Julie d'Aubigny, known as 'La Maupin', the most colorful singer of this era.
[1] It's also notable for the unusual choice of three low-lying voices for the main male parts.
Tancrède was first performed on 7 November 1702 by the Académie Royale de Musique at the Théâtre du Palais-Royal in Paris under the direction of Marin Marais.