Buphonia, in Greek antiquities, a sacrificial ceremony, forming part of the Diipolia, a religious festival held on the 14th of the month Skirophorion (June-July) at Athens, when a labouring ox was sacrificed to Zeus Polieus as protector of the city in accordance with a very ancient custom. The ox was driven forward to the altar, on which grain was spread, by members of the family of the Kentriadae (from κέντρον, a goad), on whom this duty devolved hereditarily. When it began to eat, one of the family of the Thaulonidae advanced with an axe, slew the ox, then immediately threw away the axe and fled. The axe, as being polluted by murder, was now carried before the court of the Prytaneum (which tried inanimate objects for homicide) and there charged with having caused the death of the ox, for which it was thrown into the sea. Apparently this is an early instance analogous to deodand (q.v.). Although the slaughter of a labouring ox was forbidden, it was considered excusable in the exceptional circumstances; none the less it was regarded as a murder.
Porphyrius, De Abstinentia, ii. 29; Aelian, Var. Hist. viii. 3; Schol. Aristoph. Nubes, 485; Pausanias, i. 24, 28; see also Band, De Diipoliorum Sacro Atheniensium (1873).