Opera is full of courtesans and lechers and in the 20th century, outright acts of perversion. (Salome, anyone?) But you have to go back almost 350 years for the work with the most depraved protagonist of all: Eliogabalo, by Francesco Cavalli. Based on the life of the Roman emperor Heliogabalus, who reigned from 218 to 222, the opera tells the story of a man who even today remains notorious for his sexual appetites, his appointment of an all-female senate, and his well-deserved assassination. Cavalli (1602-1676) died without ever seeing a performance of the opera, which was written for the Venice festival of 1668 but was withdrawn and replaced by another opera on the same subject. Ignored for centuries, Cavalli's opera finally received its world premiere in 1999 in Crema, Italy, the composer's birthplace.