Cavalli, Eliogabalo (Venice, 1668), opera in three acts, libretto by Aurelio Aureli after an anonymous original. Composed 1667 for the Venetian carnival of 1668, never staged in Cavallis lifetime; world premiere 27 November 1999 at the Teatro San Domenico, Crema. Sources: Wikipedia, "Eliogabalo" (https://en.wikipedia.org/wiki/Eliogabalo), which cites Ellen Rosand (ed.), Readying Cavallis Operas for the Stage, and Mauro Calcagno, "Censoring Eliogabalo in Seventeenth-Century Venice", Journal of Interdisciplinary History 36:3; and the disc of the 1999 premiere in the archive, whose back cover reads "FRANCESCO CAVALLI (Crema 1602 - Venezia 1676) ELIOGABALO (Venezia 1668), Opera in tre atti, Libretto: Aurelio Aureli". A staged opera, not a concert work, so within scope; findopera held no row for it under Eliogabalo, Heliogabalo or any shorter prefix.