Painting: Adoration of the Magi. Author: Giotto. 1304-1306.
Taken from http://www.wikipaintings.org/en/giotto/adoration-of-the-magi-1306
Epiphany (“manifestation” in Greek) is one of the earliest Christian celebrations, devoted originally to commemoration of the Nativity, adoration and Baptism of Jesus Christ. In the course of history the meaning of the feast, its traditions and customs have changed in different Christian communities. Thus, today the nativity is mainly celebrated as Christmas holiday, while adoration of Magi and Baptism of Christ are usually commemorated 12 days after Christmas, with diverse accents in the Catholic and Orthodox churches.
The name “Epiphany” has assumed a renewed meaning, as a revelation of God the Son as a human being in Jesus Christ. To point out the revelation of the Trinity (God the Father, God the Son and the Holy Spirit) also the name “Theophany” was introduced for the feast, that is “a vision of God” from Greek.
In the Catholic tradition Epiphany falls usually on January 6, it is considered the last feast closing the Christmas period. In fact, in some countries this holiday is called also “The Twelfth Night”. In Ireland Epiphany is known as “Little Christmas”, recalling the date in the old, Julian calendar, while in many other countries of the Western Europe the name for the feast is "The Three Kings Day".
Due to the differences in religious calendars the Orthodox church celebrates Epiphany, or Baptism of Jesus, on January 19.