The twelve days of Christmas end with the Feast of Epiphany also called "The Adoration of the Magi" or "The Manifestation of God." Celebrated on January 6, it is known as the day of the Three Kings (or wise men/magi): Caspar, Melchior and Balthasar. The three kings saw a bright star on the night when Christ was born, followed it to Bethlehem and found there the Christchild and presented it with gold, frankincense and myrrh.
The history of Christmas, (the festival of the nativity of Jesus Christ,) is intertwined with that of the Epiphany. The commemoration of the Baptism (also called the Day of Lights, i.e. the Illumination of Jesus) was also known as the birthday of Jesus, because he was believed to have been born then of the Virgin
or reborn in baptism. In some records Christmas and Epiphany were referred to as the first and second nativity; the second being Christ's manifestation to the world.
In the fourth century, December 25 was finally adopted by the Western Christian Church as the date of the Feast of Christ's birth. It is believed that this change in date gave rise to the tradition of the "12 Days of Christmas." While the Western Christian Church celebrates December 25th, the Eastern Christian Church to this day recognizes January 6 as the celebration of the nativity.
January 6 was also kept as the physical birthday in Bethlehem. In the Teutonic west, Epiphany became the Festival of the Three Kings (i.e. the Magi), or simply Twelfth day.
On the evening before Three Kings, traditionally there were prayers, blessed dried herbs would be burnt and their aromatic smell would fill the house. Doorways would be sprinkled with holy water and the master of the house would write with chalk C + M + B and the year above the house and barn door and say: "Caspar, Melchior, Balthasar, behütet uns auch für dieses Jahr, vor Feuer und vor Wassergefahr." ("CMB, protect us again this year from the dangers of
fire and water.") C + M + B has traditionally been translated with Caspar, Melchior and Balthasar, however, according to the Church it stands for "Christus Mansionem Benedictat" (Christ bless this home).
Epiphany used to be a fixed feast and was always on January 6, ending the 12 days of Christmas. The Church has now moved the feast to the second Sunday after Christmas. Epiphany is a large celebration, especially in Spanish speaking countries. Things look different around the household: the infant Jesus in the manger now has a small gold crown and is wearing regal robes. The figures of the wise men have reached Bethlehem, completing the nativity scene.
It was traditional to bless water on the vigil of Epiphany. This water was then used in the blessing of homes on the following day. Many pastors also blessed pieces of chalk for each family to use in inscribing the names of the three Magi over their doorways, as a manifestation of their Christian faith and a protection against the powers of evil.
The Church extends itself on Epiphany to the homes of the faithful. The custom of blessing the home probably grew up on account of the words in the Gospel, And they adored Him. The priest blesses the house if he can be present, but if not, the father (or head) of the family may do so.