Christmas Girls

The earliest known reference to the date of the nativity as December 25 is found in the Chronography of 354, an illuminated manuscript compiled in Rome. In the East, early Christians celebrated the birth of Christ as part of Epiphany (January 6), although this festival emphasized celebration of the baptism of Jesus.
Christmas was promoted in the Christian East as part of the revival of Catholicism following the death of the pro-Arian Emperor Valens at the Battle of Adrianople in 378. The feast was introduced to Constantinople in 379, and to Antioch in about 380. The feast disappeared after Gregory of Nazianzus resigned as bishop in 381, although it was reintroduced by John Chrysostom in about 400.
- Middle Ages
In the Early Middle Ages, Christmas Day was overshadowed by Epiphany, which in the west focused on the visit of the magi. But the Medieval calendar was dominated by Christmas-related holidays. The forty days before Christmas became the "forty days of St. Martin" (which began on November 11, the feast of St. Martin of Tours), now known as Advent. In Italy, former Saturnalian traditions were attached to Advent. Around the 12th century, these traditions transferred again to the Twelve Days of Christmas (December 25 – January 5); a time that appears in the liturgical calendars as Christmastide or Twelve Holy Days.