In general, the term epiphany refers to a revealing moment, and more specifically denotes the appearance or manifestation of the divine.
The Festival of Epiphany is celebrated on January 6th (12 days after Christmas). This was established during the third century during the time of Clement of Alexandria. It was also sometimes called the Manifestation of the Lord and emphasized the revelation of the Incarnation, namely, God becoming man in the person of Jesus Christ. Initially it focused on His birth, but soon included the appearance of the star, the visit of the Magi, Jesus’ baptism, and sometimes even His first miracle. In celebrating Epiphany in the church today, the Eastern Church focuses on the Baptism of Jesus, but for the Western Church, the visit of the Sages remains the emphasis. This visit reveals Jesus, not only as the Messiah, but also as Savior to the Gentiles.
In the Lutheran church, the season of Epiphany begins on January 6th and continues until the Sunday just before Ash Wednesday, the Sunday on which we celebrate the Transfiguration of our Lord. Since the date of Easter moves, and likewise, the date of Ash Wednesday, the length of the Epiphany season varies from year to year.