The San Francisco Girls Chorus (SFGC) presents its Premier Ensemble in a semi-staged performance of Vivaldi’s Juditha Triumphans at Z Space. The only oratorio by Vivaldi to have survived, Juditha Triumphans is based on the Apocryphal Book of Judith. This remarkable oratorio from 1716 was written for an all-female ensemble, with all characters both male and female interpreted by women of the Ospedale della Pietà, a girl’s orphanage in Venice where Vivaldi was music director. SFGC’s Premier Ensemble, which the San Francisco Classical Voice describes as “a dream… with beautiful dynamic shadings,” undertakes Vivaldi’s momentous work with music direction by Valérie Sainte-Agathe and stage direction by Celine Ricci.