This blessing of the home and inscription of the initials of the three Magi above each door can be performed either by a priest or the father of the family.
The feast of Epiphany, is traditionally celebrated the 12th day after Christmas, January 6th. In the dioceses of the United States this feast has been moved to the Sunday between January 2 and January 8.
After the prayers of the blessing are recited, each room of the home is sprinkled with Epiphany water. The initials of the Magi are inscribed upon the doors with chalk. (The initials, C [Casper], M [Melchior], B [Balthasar], can also be interpreted as the Latin phrase “Christus mansionem benedicat” which means “Christ bless this house”.)
Example: 20 + C + M + B + 17