Orgia

In ancient Greek religion, an orgion (ὄργιον, more commonly in the plural orgia) was an ecstatic form of worship characteristic of some mystery cults.

[1] The orgion is in particular a cult ceremony of Dionysos (or Zagreus), celebrated widely in Arcadia, featuring "unrestrained" masked dances by torchlight and animal sacrifice by means of random slashing that evoked the god's own rending and suffering at the hands of the Titans.

[5] Orgia may have been earlier manifestations of cult than the formal mysteries, as suggested by the violently ecstatic rites described in myth as celebrated by Attis in honor of Cybele and reflected in the willing self-castration of her priests the Galli in the historical period.

[7]Initiates of the Orphic and Bacchic orgia practiced distinctive burial customs (see Totenpass) expressive of their beliefs in an afterlife; for instance, it was forbidden for the dead to wear wool.

[10] Isidore of Seville says that the Latin equivalent of orgia was caerimoniae (English "ceremonies"), the arcane rites of ancient Roman religion preserved by the various colleges of priests.