WIKIPEDIA: Christmas or Christmas Day is an annual holiday generally celebrated on December 25[2][3][4] by billions of people around the world. It is a Christian feast that commemorates the birth of Jesus Christ,[5][6]liturgically closing the Advent season and initiating the season of Christmastide, which lasts twelve days.[7] In much of the world’s nations Christmas is a civil holiday,[8][9][10] is celebrated by an increasing amount of non-Christians,[1][11][12] and is an integral part of the Christmas and holiday season.
The precise day of Jesus’ birth, which historians place between 7 and 2 BC, is unknown. In the early-to-mid 4th century, the Christian Church in the West first placed Christmas on December 25, a date later adopted also in the East.[13][14] Theories advanced to explain that choice include that it falls nine months after the Christian celebration of the conception of Jesus,[15] that it was the date of the Romanwinter solstice,[16] or of some ancient winter festival.[15][17]
The original date of the celebration in the East was January 6 (see Epiphany) and that is still the date of the celebration in Armenia, where it is a public holiday, and for the Armenian Apostolic Church.
In the present century there is a difference of 13 days between the Julian Calendar and the more generally used Gregorian Calendar. Those who use the Julian calendar or its equivalents thus celebrate December 25 and January 6 on what for the majority of people is January 7 and January 19. For this reason, Ethiopia celebrates Christmas, both as a Christian feast and as a public holiday on what in the Gregorian Calendar is January 7.[18]
Many of the popular celebratory customs associated in various countries with Christmas have pre-Christian or secular themes and origins. Popular modern customs of the holiday include gift-giving, music, an exchange of Christmas cards, church celebrations, a special meal, and the display of various decorations; including Christmas trees, lights, garlands, mistletoe, nativity scenes, and holly. In addition, several figures, known as Saint Nicholas, Father Christmas, and Santa Claus, among other names, are associated with bringing gifts to children during the Christmas season.[19]