A betrothal feast is in progress, for Gyges has become King of Lydia and is to wed Nisia. Courtiers and nobles are present. The priests enter to conduct the marriage ceremony. They bring a sacrificial table. Gyges, crowned, leads his bride towards the table, places a hand over the holy flame and takes a vow. Nisia does the same, but the flame expires and there is a clap of thunder. The people are astonished at this portent and the priests withdraw from the table. Gyges, enraptured with Nisia, ignores the warning, takes the Queen towards the gardens and commands the festival to begin.