In Irish folklore, it was very unlucky to start something new. It was also believed that whichever day of the week the feast fell, that day would be unlucky throughout the following year.
On this day Herod apparently ordered the slaughter of all first-born – making “childermas” one of the unluckiest day in folk custom. Don’t start any business ventures or journeys, to be sure don’t start anything. The “boy bishops” were de-throned on this day. But this medieval tradition has died long ago, in today’s Ireland you find no young adult taking over a bishop’s throne over the Christmas period.