These fourteen essays derive from a colloquium organised by the Asociation Homo Religiosus-Luxembourg' in 1996 and address the subject of religious celebrations in the Greco-Roman world. Both specific topics, such as the origins of Greek religious celebrations in the Minoan and Mycenaean worlds, conflict between imperial cults and Christianity, celebrations in Homer and Pindar, and the Dionysus cult in Asia Minor, and more general manifestations of religious devotion are discussed: processions, priests, libations and offerings, sacrifices, banquets, music, hymns and dance. French text.