In May 1578 Emperor Rudolf II returned to Vienna to participate in a Corpus Christi procession. It was the first time in fifteen years that a Habsburg emperor had played a major role in this ecclesiastical ceremony. The feast of Corpus Christi was one of the most important festivals of the resurgent Catholic church. Celebrating the doctrine of transubstantiation, the highlight of the festivities was an elaborate procession that included the leading civic and religious leaders of a local municipality. In Vienna this holiday had long been a source of tension between the city's Catholic and Protestant population. In 1549 a Lutheran baker's apprentice had snatched a monstrance from a priest and trampled it under foot. Soldiers apprehended him immediately, chopped off his hands and cut out his tongue. The unfortunate youth was then carted outside the city and burned at the stake. Maximilian was aware of the controversy surrounding the holiday and normally did not participate in the proceedings. Emperor Rudolf did not share his father's reservations, however, and in spring 1578, accompanied by his brothers Ernst and Maximilian, he publicly displayed his allegiance to the church by joining the ecclesiastical procession.

The proceedings began smoothly, but when the cavalcade of priests, princes and magistrates turned down the Graben on their way to St. Stephen's Cathedral they encountered an unexpected bustle of activity. At the corner of the Graben and Kohlmarkt a group of farmers had set up booths selling butter, eggs and milk. As the procession passed by, a throng of onlookers surged forward. In the rush to catch a glimpse of the emperor and his retinue they toppled the milk stalls.