Today we celebrate the arrival of the three wise men who have been following the star and edging their way towards the crib. In many European countries there is a custom known as chalking the door which invites people to put the year at either end of the initials of the three wise men
Caspar - C Melchior - M Balthasar - B
20 + C + M + B + 21
Their initials C M B above the door, also stands for Christus Mansionem Benedicat, which is Latin for “May Christ Bless this House.”