Hydria from Caere (Cerveteri, Italy), dating to the VI century B.C., now in the Kunsthistorisches Museum, Vienna, Austria. The painting shows some scenes with erotic intercourses between Maenads and Sileni, emphasizing the overwhelming energy which hauled Dionysus’s followers, making them to become part of the vital power of the cosmos. On the other hand, Dionysus was the master of the awakening of nature, of the self-transforming life, of vegetation which dies and is reborn again and he was associated with seasonal ceremonies celebrating the periodic renewal which reveals the holiness of the union between life and death. The association, in a ritual context, between sexual intercourse and agricultural ceremonies is justified as a participation to the generative powers of the earth and at the same time to the reproductive process of both animals and humans.

[Source: http://library.artstor.org/library/]