I first learned about the Epiphany custom of chalking above the threshold door when I visited my German "sister" Claudia a few years ago. I loved the idea so we have done it at our home in England ever since.
So why do people chalk this combination of numbers and letters above the door- sometimes on 12th night, sometimes on the first Sunday in Epiphany?
The idea is to write in chalk above the door of a house or church the number of the year, enclosing the letters C, M and B, which stand for the Latin Christus Mansiones Benedicat – ‘May Christ Bless this House’.
The letters are also the first letters of the traditional names of the travellers, wise men or kings who legend says were called Caspar, Melchior and Balthasar.
Bible scholars may say no-one knows how many travellers there were or what their names were but the thing about Faith is you take a lot of things on faith. It doesn't really matter what their names were, it's still a nice idea and so we chalk above our door the letters and numbers which will stay there until next year.