Thésée (Theseus) is a tragédie en musique, an early type of French opera, in a prologue and five acts with music by Jean-Baptiste Lully and a libretto by Philippe Quinault based on Ovid's Metamorphoses. It was first performed on 11 January 1675 by the Paris Opera for the royal court at the Château de Saint-Germain-en-Laye and was first performed in public in April at the Théâtre du Palais-Royal in Paris.