The Feast of Fools was a feast day celebrated by the clergy in Medieval Europe. Similar to Carnival the central theme was a brief social ‘revolution’ or inversion of social norms in which power, dignity (and impunity) is briefly enjoyed by those in a subordinate position.
A mock bishop or pope was elected (often the youngest or most subordinate choirboy in the church) ecclesiastical ritual was parodied, and low and high officials changed places.
Current opinion is that far from turning the world ‘upside down’ the feast maintained the social order. By the allowing the lower orders to let off steam in buffoonery and parody tensions between them and their ‘superiors’ were diffused.
The ‘abuses’ and ‘extravagances’ of the Feast of Fools (mock sermons, drunken processions and lewd blessings) were frequently roundly condemned by the medieval Church but these customs proved remarkably durable. At Notre Dame in the twelfth century the celebration was not completely banned, but the part of the ‘Lord of Misrule’ (or Boy Bishop) was restrained.
The Feast of Fools was finally outlawed on pain of severe penalties by the Council of Basel in 1431 and a strongly worded document issued by the theological faculty of the University of Paris. Still occurrences of similar festivals are recorded in France as late as 1644.