The Orphic and Bacchic Mysteries were related religious movements centering on Dionysos and offering worshippers hope for life after death.
O happy he! who to his joy is initiated in heavenly mysteries and leads a holy life joining heart and soul in Bacchic revelry upon the hills, purified from every sin.
Euripidies, The Bacchae.
The Bacchic mysteries were held across Greece and, later, in Rome as well. Like the Elusinian mysteries, they involved initiations and offered hope of life after death, probably symbolized by the story of Dionysos's death and resurrection.
Unfortunately, we have considerably less idea of what went on at the Bacchic mysteries than at the Elusinian. Much less writing about them has survived. There was no great central temple where the Bacchic mysteries were held, as there was at Elusis, and it is possible that different groups of Bacchics worshipped differently.
A series of wall paintings discovered at Pompeii seem to show a Bacchic initiation. Central parts of the scene involve flagellation of the initiate and the unveiling of an erect phallus or herm.
Drinking wine was also most probably a part of the Bacchic's worship, and Bacchic revelers are said to have run wild in the woods as maenads, handling live snakes, and tearing wild animals apart and eating their flesh raw. Human sacrifice may also have played a role. In Rome, the Dionysaic Bacchanalia was banned for a time due to these supposed excesses. These aspects of Bacchic worship are shrouded in controversy.
Orphism was a somewhat more scholarly, book-centered religion, sort of the flip side of Bacchism. The relationships between the two movements are uncertain, but the groups seem to have shared some myths. The Orphics are said to have been ascetic, vegetarian, and greatly interested in theology.
The Orphic gods are, at first glance, identical to those found in mainstream Greek religion. The difference is one of emphasis and interpretation; the Orphic writers went to great lengths to elaborate on their ideas about the gods. They developed their own cosmogonies, or accounts of creation, which are quite different from those in the standard Theogony of Hesiod.
According to Plato, discussing the word for soul, soma, which can also be translated as safe, "the Orphic poets gave it this name with the idea that the soul is undergoing punishment for something; they think that it (the soul) has the body as an enclosure to keep it safe, like a prison"
The reason for the punishment is alluded to in a passage Plato quotes from Pindar, in the Meno. The passage reads: "But those at whose hands Persephone accepts atonement for her ancient grief, their souls in the ninth year she sends up again to the sun of this world … and for all time to come they are called of men holy heroes."
The ancient grief of Persephone, according to an argument by the classicist H. Rose, is sorrow for the death of her son Dionysos at the hands of the Titans. Humans pay the punishment because they were born from the Titan's ashes. By living an Orphic life and avoiding the shedding of blood which is the legacy of the Titans, humans may pay the penalty and achieve freedom.