Canon Mark Madden explains the Epiphany tradition of Chalking the Door
Epiphany marks the occasion of a time-honoured Christian tradition of “chalking the doors.” The formula for the ritual is simple: take chalk and write the following above the entrance of your home:
20 + C + M + B + 21
The “20” at the beginning and the “21” at the end mark the current year.
The four crosses separating the numbers and letters represent Jesus being at the centre of everything we do this year.
The letters C M B have two meanings. First, they represent the initials of the Magi — Caspar, Melchior, and Balthazar — who came to visit Jesus in Bethlehem.
They also abbreviate the Latin phrase, Christus mansionem benedicat: “May Christ bless this house.”
Taken together, this is a request for Christ to bless our home and all those who visit throughout the entire year.