Among countries with a strong Christian tradition, a variety of Christmas celebrations have developed that incorporate regional and local cultures. After Christmas and Epiphany were in place, on December 25 and January 6, with the twelve days of Christmas in between, Christians slowly adopted a period called Advent, as a time of spiritual preparation leading up to Christmas.

Main article: Date of birth of Jesus Mosaic in Mausoleum M in the pre-fourth-century necropolis under St Peter's Basilica in Rome, interpreted by some as Jesus represented as Christus Sol (Christ the Sun). [50] Heinz, Donald (2010). Christmas: Festival of Incarnation. Fortress Press. p.94. ISBN 978-1-4514-0695-5. The School Journal, Volume 49. Harvard University. 1894 . Retrieved April 2, 2009. Throughout the Christian world the 25th of December is celebrated as the birthday of Jesus Christ. There was a time when the churches were not united regarding the date of the joyous event. Many Christians kept their Christmas in April, others in May, and still others at the close of September, till finally December 25 was agreed upon as the most appropriate date. The choice of that day was, of course, wholly arbitrary, for neither the exact date not the period of the year at which the birth of Christ occurred is known. For purposes of commemoration, however, it is unimportant whether the celebration shall fall or not at the precise anniversary of the joyous event. Holidays at the Museums: Carnegie Museum of Natural History". Carnegiemnh.org. November 26, 2013. Archived from the original on December 27, 2013 . Retrieved December 25, 2013.West's Federal Supplement. West Publishing Company. 1990. While the Washington and King birthdays are exclusively secular holidays, Christmas has both secular and religious aspects. Norris, Rebecca (October 29, 2019). "Here's the History Behind Why Red and Green Are the Traditional Christmas Colors". Country Living . Retrieved December 18, 2020. The English word "Christmas" is a shortened form of "Christ's Mass". The word is recorded as Crīstesmæsse in 1038 and Cristes-messe in 1131. [24] Crīst ( genitive Crīstes) is from Greek Khrīstos (Χριστός), a translation of Hebrew Māšîaḥ (מָשִׁיחַ), " Messiah", meaning "anointed"; [25] [26] and mæsse is from Latin missa, the celebration of the Eucharist. [27]

The prominence of Christmas Day increased gradually after Charlemagne was crowned Emperor on Christmas Day in 800. King Edmund the Martyr was anointed on Christmas in 855 and King William I of England was crowned on Christmas Day 1066. The Provençal Nativity Scene". Simplytreasures.com. Archived from the original on September 14, 2012 . Retrieved December 25, 2013. Saint Nicholas, known as Sinterklaas in the Netherlands, is considered by many to be the original Santa Claus [233]Correspondence between Julian December 25 and Gregorian January 7 of the following year holds until 2100; from 2101 to 2199 the difference will be one day more. [ citation needed] Roll, Susan K. (1995). Toward the Origins of Christmas. Peeters Publishers. p.130. ISBN 978-90-390-0531-6. Archived from the original on November 2, 2015 . Retrieved June 20, 2015. Christian church of God – history of Christmas". Christianchurchofgod.com. Archived from the original on December 19, 2010 . Retrieved February 24, 2011.

Some jurisdictions of the Eastern Orthodox Church, including those of Russia, Georgia, Macedonia, Montenegro, Serbia, and Jerusalem, mark feasts using the older Julian calendar. As of 2023, there is a difference of 13 days between the Julian calendar and the modern Gregorian calendar, which is used internationally for most secular purposes. As a result, December 25 on the Julian calendar currently corresponds to January 7 on the calendar used by most governments and people in everyday life. Therefore, the aforementioned Orthodox Christians mark December 25 (and thus Christmas) on the day that is internationally considered to be January 7. [241]Christmastide, Christmas Eve, Advent, Annunciation, Epiphany, Baptism of the Lord, Nativity Fast, Nativity of Christ, Old Christmas, Yule, St. Stephen's Day, Boxing Day Current tradition in several Latin American countries (such as Venezuela and Colombia) holds that while Santa makes the toys, he then gives them to the Baby Jesus, who is the one who actually delivers them to the children's homes, a reconciliation between traditional religious beliefs and the iconography of Santa Claus imported from the United States. Post-classical history The Nativity, from a 14th-century Missal; a liturgical book containing texts and music necessary for the celebration of Mass throughout the year Presepi in Liguria: provincia di Genova, Tigullio -sito di Paolino". Digilander.libero.it. Archived from the original on December 27, 2013 . Retrieved December 25, 2013.