Feast of Fools, the name of a festival regularly celebrated, with the most absurd ceremonies, both by clergy and laity, in several countries of Europe, from the 5th to the 16th century. It is said to have been introduced in imitation of the Roman saturnalia, and its celebration took place about the same time, the great day being New Year's; but the ceremonies were often continued from Christmas to the last Sunday of Epiphany. The Feast of Fools was condemned by several Popes and bishops in the 15th century, and the Council of Basel, in 1435, expressed its detestation of this and several other festivals; but it continued to be observed in many places down to the time of the Reformation.
Entry from Everybody's Cyclopedia, 1912.