December 28 is variously called Childermas, Bairn’s Day (Scottish for child) or Día de los Santos Inocentes and commemorates Herod’s Slaughter of the Innocents related in Mathew 2.
The incident is not related outside of the Gospel of Matthew, and it is not mentioned by Josephus. Some regard it as creative hagiography, most historians agree that it is historically possible. Herod had done massacres before.
Others argue that based on the estimated population of Bethlehem at the time (1,000) that the largest number of infants that could have been killed would have been about 20–not on a scale to match the spectacular assassinations attributed to the day.
Perhaps because it is such dramatic picture of pride, power, and violence the incident is often portrayed in art and literature.
This is a detail from The Massacre of the Innocents by Lucas Cranch the Elder (c. 1515) from the National Museum in Warsaw.
Throughout the Spanish-speaking world, it is a day to play pranks similar to April Fool’s Day in the Anglosphere.
Bromas del Día de los santos innocements
http://www.youtube.com/watch?v=ybWrOYn6a08