A group of Cenobite monks go about their daily business. Athanaël, the most rigorous ascetic of them all, enters and confesses to the senior monk, Palémon, that he has lately been disturbed by visions of a courtesan and priestess of Venus named Thaïs, whom he had seen many years ago in his native city of Alexandria. Believing these visions to be a sign from God, he resolves, against Palémon's advice, to return to Alexandria, convert Thaïs to Christianity, and persuade her to enter a convent.