The Feast of Fools, documented most thoroughly in medieval France, saw subdeacons and other members of the lower clergy elect one of their own as a mock bishop or Lord of Misrule and stage an elaborate burlesque parody of the ordinary liturgy inside the cathedral building itself, using the very space and vestments of formal worship as the material for a day of licensed comic inversion. The clergy performing the parody were themselves genuinely ordained members of the church, not outsiders mocking it from beyond, which is precisely what allowed the day to function as Church sanctioned release rather than as open subversion, since the same men returned the following day to their ordinary place within the strict clerical hierarchy the feast had briefly turned upside down. Its timing around the turn of the calendar year, often close to the Feast of the Circumcision on the first of January, placed it within the same general midwinter season across which several cultures independently developed festivals of licensed reversal.
Surviving records describe specific burlesque acts performed as part of the parody, including clergy braying like donkeys in place of liturgical responses and censing the altar with the smoke of old shoe leather rather than incense, details vivid enough that later hostile reformers cited them directly as evidence of how far the observance had strayed from anything defensible as sanctioned religious humour.