This paper attempts to reconcile, what appear to be, two conflicting accounts of authenticity in Heidegger's thought. Authenticity in Being and Time (1927) is commonly interpreted in 'existentialist' terms as willful commitment and resoluteness (Entschlossenheit) in the face of one's own death but, by the late 1930's, is reintroduced in terms of Gelassenlieit, as a non-willful openness that "lets beings be." By employing Heidegger's conception of authentic historicality (Geschiclidichkeit), understood as the retrieval of Dasein's past, and drawing on his writings on Hölderlin in the 1930'sand 1940's, I suggest that the ancient interpretation of leisure and festivity may play an important role in unifying these conflicting accounts. Genuine leisure, interpreted as a form of play (Spiel), frees us from inauthentic busy-ness and gives us an opening to face the abyssal nature of our own being and the mystery that "beings are" in the flrst place. To this end, leisure re-connects us with wonder (Erstaunen) as the original temperament of Western thought. In leisurely wonder, the authentic self does not seek purposive mastery and control over beings but calmly accepts the unsettledness ofbeing and is, as a result, allowed into the original openness or space of play of time (Zeit-Spiel-Raum) that lets beings emerge-into-presence on their own terms.