

Chalking the door is a ChristianEpiphanytide tradition used tobless one's home.[1] It is normatively in the pattern of fourcrosses positioned in between the traditional initials of thethree wise men, which are surrounded by the first two and last two digits of the current year (e.g. 20 ✝ C ✝ M ✝ B ✝ 25).[2] The practice of chalking the door originated in medievalEurope, though it has spread throughout worldwideChristendom.[3][4]
Either onTwelfth Night (5 January), thetwelfth day ofChristmastide and eve of the feast of the Epiphany, or onEpiphany Day (6 January) itself, many Christians (includingAnglicans,Episcopalians,Lutherans,Methodists,Presbyterians andRoman Catholics, among others) write on their doors orlintels withchalk in a pattern such as "20 ✝ C ✝ M ✝ B ✝ 25". The numbers in this example refer to the calendar year 2025 and thecrosses toChrist. The letters C, M, and B stand for the traditional names of thebiblical Magi (Caspar,Melchior andBalthazar), or alternatively for the LatinblessingChristus mansionem benedicat ('May Christ bless this house'),[5] or IIIK referring to the three kings[citation needed].
Chalking the door is done most commonly on Epiphany Day itself. However, it may be done on any day within theEpiphany season.[6] In some localities, the chalk used to write the Epiphanytide pattern is blessed by a Christian priest or minister on Epiphany Day, then taken home to write the pattern.[7]
The Christian custom of chalking the door has a biblical precedent as theIsraelites in theOld Testamentmarked their doors in order to be saved from death; likewise, the Epiphanytide practice serves to protect Christian homes fromevil spirits until the next Epiphany Day, at which time the custom is repeated.[8] Families also perform this act to represent the hospitality of theHoly Family to the Magi (and allGentiles); it thus serves as ahouse blessing to invite the presence ofGod in one's home.[9][a]
In 20th centuryPoland, the practice of chalking the door continued among believers as another way of asserting their Christian identity, despite theEastern Bloc'sstate atheism andanti-religious campaigns.[11]
The church has some wonderful Epiphany traditions. In Germany, where I was stationed, it was not unusual to walk past a house and see a chalk inscription that read: "20 ✝ C ✝ M ✝ B ✝ 24." "CMB" stands for Caspar, Melchior and Balthazar, the traditional names of the Magi. "20" and "24" mark the coming year (2024). Others say "CMB" is an abbreviation of a blessing:Christus mansionem benedicat, which is Latin for "May Christ bless this house."