Isis, which premiered January 5, 1677, at St. Germain-en-Laye, was the fifth of Jean-Baptiste Lully's tragédies lyriques written with librettist Philippe Quinault. The plot is loosely adapted from one of the episodes in Ovid's Metamorphoses. In many of its essentials, the plot of Isis resembles that of Lully's previous opera, Atys. In Isis, the nymph Io, daughter of the river Inachus, is promised in marriage to Hierax, just as the nymph Sangaride, daughter of the river Sangar, was promised to Celoenus. Like Sangaride, Io is pursued by another love and yields to this love in spite of her feelings of guilt. Like Sangaride, Io has a goddess as a rival and is vulnerable to her jealousy. Lully's contemporaries interpreted this story as representing the volatile situation between two of the King's mistresses. The subsequent scandale of the premiere ended the collaboration between Lully and Quinault for a time, and led to the dismissal of a number of members of Lully's artistic circle.
Thesée, which premiered at the court theater at St. Germain-en-laye on January 11, 1675, was Jean-Baptiste Lully's third tragédie lyrique created in collaboration with librettist Philippe Quinault. As in most of his libretti for Lully, Quinault combines a plot based on a classical source (an episode from Ovid's Metamorphoses) with references to contemporary events. The Prologue alludes to Louis XIV's personal leadership in the military engagements in the Alsace (along the French/German border). The juxtaposition of Venus' entreaties for pleasure with Mars' call to arms reflects a period of unease during which the French armies were in retreat from the armies of the Elector of Brandenburg. This resulted in the unique joining of songs of love with songs of war and victory.