The rite was called the Buphonia, the "ox-murder," performed during the midsummer festival of the Dipolieia. The traveler Pausanias recorded the procedure with evident fascination but a careful refusal to explain why. Barley mixed with wheat was placed on the altar and left alone. The waiting ox approached and ate. The ox-slayer killed it, cast aside his axe "according to the ritual," and fled the scene. Then the others gathered up the weapon and carried it to a formal court - "as though they know not the man who did the deed." The killing of a working ox, an animal that plowed and labored alongside its owners, was treated not as routine sacrifice but as something close to homicide.

The trial unfolded as an absurdist chain of blame. Because the ox-slayer had vanished, the accusation fell first on the young women who had carried water to sharpen the blade. They pointed to the men who actually sharpened it. The sharpeners blamed the man who handed over the axe and knife. He blamed the butcher who struck the blow. And the butcher blamed the knife itself. The knife, of course, could mount no defense - so the knife was convicted of the murder and, by some accounts, ceremonially flung into the sea. The Athenians had built an entire judicial pageant to absorb the guilt of taking a useful animal's life.

The strangest act came last. Once the meat had been distributed and eaten, the ox's hide was stuffed with straw, sewn up, and stood back on its feet. The reassembled animal was then harnessed to a plow, as if to undo the death and return the beast to its work. It was a ritual of denial and repair, a community insisting that the ox lived on, that no one was truly responsible, that the city protected by Zeus had not really shed innocent blood. Behind the strangeness lies a genuine moral discomfort - the unease of an agricultural people about killing the creatures they depended on.

Almost nothing survives to mark where this happened. No foundations have been excavated. The sanctuary's shape - a trapezoidal enclosure with several entrances, built around 500 BC - is reconstructed entirely from cuttings carved into the living bedrock of the Acropolis, just east of the Erechtheion. The eastern part of the precinct is thought to have held the oxen kept ready for sacrifice. The main entrance once carried a sculpted pediment. Pausanias noted two statues of Zeus here, one of them by the sculptor Leochares. Today a visitor finds only worn rock and faint grooves - the ghost of a place where Athens once tried, every summer, to forgive itself.