Scarlatti’s Griselda is based on a story from the Decameron. Gualtiero, king of Sicily, has married Griselda, a shepherdess. The people are upset that the king has married beneath him and are getting stroppy. Gualtiero sets out to prove Griselda a worthy consort by testing her constancy. He repudiates Griselda and sends her back to shepherding while arranging to marry an Apulian princess Constanza, who both he and Corrado, duke of Apulia, know to be his daughter by Griselda. It’s complicated by one Ottone who is infatuated by Griselda and Roberto, son of Corrado, who is in love with Costanza, who returns his feelings. Griselda is put through various humiliating trials in which she repeatedly shows her devotion to Gualtiero. Eventually the people recognise her virtue and all is restored. One notable thing, unlike his predecessor Cavalli, Scarlatti doesn’t inject any incongruous or comic passages into the opera. It’s all deadpan serious.