Cervulus refers to a Pagan feast day, about which little is known. Remnants of the feast have been incorporated into the Christian ceremony Festival of the Asses (Festum Asinorum), which honors the role of donkeys in the Bible, including Mary's flight into Egypt. Some accounts of the Christian version of the festival say that a pregnant woman from a village would ride a donkey to a local church. In Bauvais, each operation of the mass, instead of saying "Amen" the congregation would bray "Y-a" There the donkey would stand near the altar during the saying of the mass.