INNOCENTS' DAY, or CHILDERMAS, a festival celebrated in the Latin church on the 28th of December, and in the Greek church on the 29th (O.S.) in memory of the massacre of the children by Herod. The Church early regarded these little ones as the first martyrs. It is uncertain when the day was first kept as a saint's day. At first it seems to have been absorbed into the celebration of the Epiphany, but by the 5th century it was kept as a separate festival. In Rome it was a day of fasting and mourning. In the middle ages the festival was the occasion for much indulgence to the children. The boy-bishop (q.v.), whose tenure of office lasted till Childermas, had his last exercise of authority then, the day being one of the series of days which were known as the Feast of Fools. Parents temporarily abdicated authority, and in nunneries and monasteries the youngest nun and monk were for the twenty-four hours allowed to masquerade as abbess and abbot. These mockeries of religion were condemned by the Council of Basel (1431); but though shorn of its extravagances the day is still observed as a feast day and merrymaking for children in Catholic countries, and particularly as an occasion for practical joking like an April Fool's Day. In Spanish-America when such a joke has been played, the phrase equivalent to "You April fool!" is Que la inocencia le valgat May your innocence protect yoa! The society of Lincoln's Inn specially celebrated Childermas, annually electing a " king of the Cockneys." Innocents' Day was ever accounted unlucky. Nothing was begun and no marriages took place then. Louis XI. prohibited all state business. The coronation of Edward IV., fixed for a Sunday, was postponed till the Monday when it was found the Sunday fell on the 28th of December. In rural England it was deemed unlucky to do housework, put on new clothes or pare the nails. At various places in Gloucestershire, Somerset and Worcestershire muffled peals were rung (Notes and Queries, 1st series, vol. viii. p. 617). In Northampton the festival was called " Dyzemas Day " (possibly from Gr. 6wr- " ill " and "mass "), and there is a proverb "What is begun on Dyzemas will never be finished." The Irish call the day La Croasla na bliana, " the cross day of the year," or Diar dasin darg, " blood Thursday," and many legends attach to it (Notes and Queries, 4th series, vol. xii. p. 185). In medieval England the children were reminded of the mournfulness of the day by being whipped in bed on Innocents' morning. This custom survived to the 17th century.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)