[1] The quality of the vocal writing in Scylla et Glaucus came as a surprise to many, given that Leclair was much better known for composing instrumental music, and therefore had little experience in opera.
He received much of his musical training in Italy, where he was exposed to the influence of Pietro Locatelli and other Italian composers of the time.
[a] A temple of Venus where the people of Amathus celebrate a festival in honour of the goddess, the laws to which even the dreaded Mars himself yields.
The party is interrupted by Propoetides (the daughters of Propoetus from the city of Amathus on the island of Cyprus), who are jealous of the presence of Venus; they abhor religion and deny the divinity of the goddess.
The nymph Scylla is equally cold to all of her lovers, including Glaucus, a young prophetic sea-god in Neptune's court, born mortal and turned immortal upon eating a magical herb.
The spell is successful; Glaucus falls at Circe's feet and Scylla is quickly forgotten.
The moment the two lovers leave, she embarks upon magic incantations to take revenge on Scylla.
The Moon descends from heaven, transforms into Hecate, and from out of the Underworld brings to Circe "the most deadly poison that the Phlegethon River has ever produced form its shores".
The people of Sicily come to celebrate the anniversary of the liberation of their country, which had for years been subject to the tyrannical empire of the Cyclops.
In 1747, Jean-Marie Leclair the Younger, brother of the composer, showed the opera at the Academy of Fine Arts in Lyon, directing the orchestra.
Neal Zaslaw, an American musicologist, attributes its lack of revival to three specific aspects of the opera: Hecate's terrifying magic powers, a "thoroughly Baroque" musical style, and a tragic ending, viz.
The opera is cast in the traditional tragédie en musique form developed by Jean-Baptiste Lully in the seventeenth century: a prologue followed by five acts.