Christmas or Christmas Day (Old English: Crīstesmæsse, meaning "Christ's Mass") is an annual festival commemorating the birth of Jesus Christ, observed most commonly on December 25 as a religious and cultural celebration among billions of people around the world. A feast central to the Christian liturgical year, it closes the Advent season and initiates the twelve days of Christmastide, which ends after the twelfth night.Christmas is a public holiday in many of the world's nations, is celebrated culturally by a large number of non-Christian people, and is an integral part of the Christmas and holiday season.
While the birth year of Jesus is estimated among modern historians to have been between 7 and 2 BC, the exact month and day of his birth are unknown, and are not the focus of the Church's Christmas celebration. His birth is mentioned in two of the four canonical gospels. By the early-to-mid 4th century, the Western Christian Church had placed Christmas on December 25, a date later adopted in the East, although some churches celebrate on the December 25 of the older Julian calendar, which, in the Gregorian calendar, currently corresponds to January 7, the day after the Western Christian Church celebrates the Epiphany. The Council of Tours of 567 "declared the twelve days between Christmas and Epiphany to be one unified festal cycle", thus giving significance to both December 25 and January 6. The Second Council of Tours stated that: "There are feasts on each day between the Nativity of the Lord and Epiphany, except the three-day period on which our Fathers established for the beginning of January private Litanies in order to tread down the custom of the Gentiles. These three days it declared not to be joyful but to be days of penance and fasting. The date of Christmas may have initially been chosen to correspond with the day exactly nine months after early Christians believed Jesus to have been conceived, or with one or more ancient polytheistic festivals that occurred near southern solstice (i.e., the Roman winter solstice); a further solar connection has been suggested because of a biblical verse identifying Jesus as the "Sun of righteousness".
The celebratory customs associated in various countries with Christmas have a mix of pre-Christian, Christian, and secular themes and origins. Popular modern customs of the holiday include gift giving, completing an Advent calendar or Advent wreath, Christmas music and caroling, an exchange of Christmas cards, church services, a special meal, and the display of various Christmas decorations, including Christmas trees, Christmas lights, nativity scenes, garlands, wreaths, mistletoe, and holly. In addition, several closely related and often interchangeable figures, known as Santa Claus, Father Christmas, Saint Nicholas, and Christkind, are associated with bringing gifts to children during the Christmas season and have their own body of traditions and lore. Because gift-giving and many other aspects of the Christmas festival involve heightened economic activity, the holiday has become a significant event and a key sales period for retailers and businesses. The economic impact of Christmas is a factor that has grown steadily over the past few centuries in many regions of the world.
