The 28th of December is the 4th Day of Christmas, and the Feast of the Holy Innocents, or Childermas.
It is the commemoration of a terribly sad event. According to an account in the Gospel of Matthew, the Roman puppet-king of Judea, Herod the Great, “ordered the execution of all young male children in the vicinity of Bethlehem, so as to avoid the loss of his throne to a newborn King of the Jews whose birth had been announced to him by the Magi.” There is some historical dispute as to whether or not this actually happened, but King Herold was certainly bastard enough to have done it; he murdered a mother-in-law, a wife, and three of his own sons, so he was a cold-hearted monster capable of any atrocity.
Oddly enough, the slaughter of baby boys was turned into a Yuletide celebration in Medieval Britain with the exaltation and mockery of boy bishops. A young boy, usually a chorister in the church, was chosen to preside as the ‘bishop’ on 6th December, for St Nicholas’s Day, and “dressed in full bishop’s robes with mitre and crozier and, attended by comrades dressed as priests, made a circuit of the town blessing the people. Typically the chosen boy and his colleagues took possession of the cathedral and performed all the ceremonies and offices, except Mass.”
Theoretically hijinks would ensue, much like the Feast of Fools and other forms of seasonal merriment. The boy bishop’s reign would end with a particularly raucous party on the 28th, often involving pranks and japes that bordered on the blasphemous.
This inversion of the adult/child role was probably a pre-Christian holdover from the Roman Saturnalia, which often involved role reversal as part of the celebrations. In an effort to get such pagan shenanigans out of the Church during the Reformation, King Henry VIII abolished the election of boy bishops in 1542, declaring:
“Whereas heretofore dyvers and many superstitions and chyldysh observances have been used, and yet to this day are observed and kept, and in many and sundry parts of this realm, as upon Saint Nicholas, Saint Catherine, Saint Clement, the Holy Innocents, and such like, children be stranglie decked and apparayled to counterfeit priestes, bishoppes, and women, and so be ledde with songes and daunces from house to house, blessing the people and gatheryng of money; and boyes do singe masse and preache in the pulpitt, with suche other unfittinge and inconvenient usages, rather to the deryson than any true glory of God, or honor of his sayntes.”
The custom of boy bishops was revived by Queen Mary I in 1552, but was finally abolished for good by Protestant Queen Elizabeth I when she came to the throne, although it continued to be practiced surreptitiously in several areas of Great Britain for centuries.