Bouphonia Festival in Classical Greece

The Bouphonia, or "the Murder of the Ox" is an elaborate ceremony celebrated in Athens and elsewhere in ancient Greece. It has the peculiar element that the sacrifice was described as a "murder" and the actual sacrifice was followed by an elaborate judicial proceeding in which the sacrificer was accused of "murdering" the ox; he blamed it on the other attendants present who passed the responsibility on to other humans. Finally the ax used in the slaughter was found guilty and sentenced to death at which point it was pitched off a cliff into the sea. Oxen were often sacrificed at the larger community festivals in Greece (and cooked!--the Indo-Europeans almost never killed anything they weren't going to eat), but only this sacrifice was treated as a murder. This version of the ritual is reconstructed from a number of sources, outlined in both Frazer and Parke.

The object of the sacrifice in Athens was said to be Zeus, however, every offering was considered to be at least partly for Zeus as an important god. The more likely recipients were the honored dead. No explicit statement is known for the liturgy for the Bouphonia festival but the proper Greek prayer for the souls of the dead is known from Euripides' Iphigenia in Tauris. The Greeks normally poured a libation of wine into the ground as part of any ritual; here they offer milk, wine and honey as an offering to the dead:

Milk of the mountain kine,
Hallowed gleam of wine,
Toil of murmuring bees,
By these shall the dead have rest.

Also there is a detailed explanation of the proper way to offer wine at a Daps to the Agathos Daimon (the spirits of the dead who created our world), given in the Deipnosophists.

The festival was set for the 14th of Skirophorion, a month that began in June and continued into July, however the early calendar of the Greeks was set to the lunar schedule, so the exact date (according to the solar year) would have been different each year.

There is no exact myth in Greek sources that links the festival of the Bouphonia with the myths of the Indo-European god Yama (the Primal Cow Creation Myth), but the date (in Mediterranean countries, at the beginning of the dry season), and the peculiar elements of the ritual provide the link, according to Jaan Puhvel. See Yama article, for the development of the Proto-Indo-European god Yama into various gods and saints.

Conclusion
Although there are Greek pagan reconstructionist groups centered in Greece, it seems unlikely that they will be celebrating a festival with the killing of an ox. On the other hand, people still celebrate major festivals in many countries by roasting a whole ox, when they can afford it. The festival is retained in many Christian countries as the feast day of St. James (St. Jacobus, or Santiago), set to July 25, depending on the calendar. St. James has many features in common with the Indo-European god Yama, but the exact path of transmission is not clear.

References

Encyclopedia Britannica , Complete Home Library, Newsweek Edition, 2004

Frazer, James Golden Bough , MacMillan & Co. Ltd., London, 1919-1920 (12 vol. edition), Vol. 8, pages 4-8

Parke, H. W. Festivals of the Athenians, Cornell University Press, NY, 1977.

Puhvel, Jaan, Analecta Indoeuropaea, (a collection of articles), publ. by Innsbrucker Beitrage zur Sprachwissenschaft, Innsbruck, 1981.