History of Christmas: Why do we celebrate it on December 25?


Here begins our series of articles on the History of Christmas.

The Advent SeasonAdvent means the “coming” of the Christ Child — is marked by the four Sundays before Christmas and is celebrated in the church calendar as one the most festive seasons of the year.

As we shall see, many of the traditions, customs, and stories of the Advent Season have Christian roots while others have non-Christian sources. Some are legendary, and others are firmly rooted in history.

It is perhaps ironic that the actual date for the Nativity or birth of the Christ Child, which our Western calendar system is based upon, is not known with certainty. Indeed, the Feast of Christmas was not an early festival for the church, like Resurrection Sunday (Easter) was, and in fact did not see general observance until the 4th century. The western church did not agree upon the current date of December 25 until the early part of the 5th century under Pope Leo I, though this date for Christmas was first mentioned in the 4th century illuminated manuscript the Chronography of 354. Some historians suggested that the date of Christmas was derived as 9 months after the Annunciation (to Mary) which is celebrated on March 25. Many 18th century scholars, including Isaac Newton, argued that this date was picked to supplant the pagan year-end holiday Saturnalia that was celebrated by the Romans and many of whose customs survive today: decorations of evergreen, holly, mistletoe, feasting and the exchange of gifts.

December 25, the ancient date for their Winter Solstice, was celebrated as the birthday of the “unconquerable sun” or dies natalis solis invicti when the sun’s transit was in the lowest point on the horizon with the shortest “day” of the year and then with longer days coming began its transit northward. Under the Christian calendar the 25th was to become known as the birth of the unconquerable Son.

Bill Petro, your friendly neighborhood historian


  1. […] point of fact, as mentioned in our previous article, we don’t know with certainty what time of the year the Nativity occurred. Two millennia ago […]

  2. Science of the Winter Solstice | Bill Petro on December 21, 2009 at 2:03 am

    […] we’ve mentioned before, the Romans celebrated a holiday known as the Saturnalia beginning on the Winter Solstice. The word […]

  3. Adam H. on October 29, 2010 at 7:58 am

    There is some evidence to show the date of Christmas was specifically chosen to be 9 months from the Annunciation. If one views the Eastern Orthodox liturgical calendar one sees that the commemoration of the Conception of the Theotokos (Mary) is held on Dec. 9 and Nativity of the Theotokos is commemorated on Sept. 8, also, the Conception of John the Forerunner (also called the Baptist) is commemorated on Sept. 23 and his nativity is commemorated on June 24. Thus the Virgin Mary has 9 months, minus a day, between conception and birth and John has 9 months, plus a day, between conception and birth. I have heard some say that there is some symbolism there as well. Christ, being the perfect man, is (liturgically) in the womb exactly nine months. John and the Virgin Mary, both being prime examples for Christians are both in the womb for 9 months but since they are not perfect as Christ the time between their conception and birth is modified by a single day either way.

    • Bill Petro on October 31, 2010 at 9:34 pm

      Yes, Adam, I have heard the same story.

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