In the Liturgical calendar, today is the Feast of the Holy Innocents or Lá Crosta na Bliana or the cross day of the year in Irish. The day was also known as ‘Lá na Leanbh’ (Day of the Children). In Irish tradition this day was seen as an unlucky day because it commemorated the murder of children by King Herod.
In consequence, probably of the feeling of horror attached to such an act of atrocity, Holy Innocents’ Day used to be reckoned about the most unlucky throughout the year, and in former times, no one who could possibly avoid it, began any work, or entered on any undertaking, on this anniversary. Those who married on that day ran especially high risks of future misery. The Irish called 28th December ‘the cross day of the year’ for that reason.