Why is Christmas celebrated on December 25?
The date of December 25th
St. Luke writing the Gospel
1. December 25 is a conventional date, chosen by Christians as the birth of Jesus Christ to counter the pagan festival of the Sol Invictus, and also to superimpose other celebrations as the Jewish Hanukkah and Celtic cults linked to the astronomical calendar, or
2. December 25 is actually the historical date of the birth of Jesus, a hypothesis based on the Gospel of Luke and on the archaeological studies of the Qumran manuscripts by Israeli professor Shemarjahu Talmon.
Dies Natalis Solis Invicti
Pope John Paul II celebrating Christmas as a young cardinal
Pope Benedict XVI celebrates Christmas Mass in St. Peter's
The celebration of the Sun's Nativity was decided by emperor Aurelianus, who had established a true solar cult, linked to the god Mithra and dating back to more than a thousand years before Christ; Aurelianus, who made the sun-god the main deity of his empire and used to wear a ray-shaped crown, consecrated the temple of Sol Invictus on December 25, 274, in a celebration that was called "Dies Natalis Solis Invicti" (=Birth Day of the Unconquered Sun) which was attached to and concluded the Saturnalia, the most ancient Roman festival.
Roman coin from Palmyra, representing Aurelianus with a crown in the form of sun rays
In 337 Pope Julius I formalized the date of Christmas for the Christian Church (today divided into Catholic, Orthodox, Coptic, and Protestant in many denominations), as reported by John Chrysostom in 390, and as documented in the 'Roman Chronography', an illuminated calendar for the year 354 AD, produced by the calligrapher and illuminator Furius Dionysius Filocalus.
The Chronography of 354 AD (the calendar of Philocalus), Part 6: December
But why is the sun "born" some days after the solstice? The "death" of the sun takes place at the winter solstice (22 or 23 December). In the following 3 days the sun does not rise by any degree - from which 'Sol stitium' (= sun stop), while on December 25 the sun rises by one degree, signaling the "resurrection" of the sun and from 25 December onwards the days become longer until the equinox in March.
Therefore, cosmic symbolism inspired the leaders of the Church of Rome to elect the end of the winter solstice, December 25, as the birthday of Christ, and the end of the summer solstice, June 24, as that of John the Baptist, integrated with their dates of conception nine months earlier on the spring and autumn equinoxes, respectively.
First, as we have seen, from the 3rd century onwards the "Dies Natalis Solis Invictis" was celebrated in Rome on 25 December. It was the day of the Mithraic rites of the birth of the Sun and the end of the Saturnalia, a Roman festival celebrated in mid-December, which was the archetype of many Christmas customs, such as decorations, the exchange of gifts and lighting of candles.
"Romans during the Decadence", celebrating Saturnalia, painting by Thomas Couture, Musée d'Orsay
Thirdly, Hanukkah: in the Hebrew calendar the Jewish festival of the "Dedication" or "Festival of Lights" starts on 25 Kislev, and lasts for eight days. However, Hanukkah never falls on the same day and can go from the end of November to the end of December.
Traditions for Hanukkah: the menorah, pastries, dreidel
In ancient Israel the members of the priestly class were divided into 24 groups each consisting of six priestly families. The 24 groups, alternating in an immutable order, were to perform liturgical service at the temple for a week, twice a year, with each of the six serving one day of the week and all serving together on the Sabbath. The family of Aaron was the eighth to provide liturgical service at the temple and one of the two weeks a year assigned to it was the last week of September.
The Gospel of Luke opens with the story of an old couple, Zechariah and Elizabeth (would-be parents of John the Baptist) resigned to sterility, one of the worst misfortunes in Israel. Zechariah belonged to the priestly caste of Aaron (Luke 1:67-79), and his wife Elizabeth was a relative [Luke 1:36] of the Virgin Mary. Luke reports that one day Zechariah, "officiating in the turn of his family", that is during the week when it was the duty of Zechariah's family line to serve at "the temple of the Lord", had a vision of the archangel Gabriel (Luke 1:8-11) who announced to him that, despite his advanced age, he and his wife would have a son, they were to call him John and this son was to be "great before the Lord".
Domenico Ghirlandaio, "Annunciation to St. Zechariah in the Temple", Cappella Tornabuoni, Florence.
If Jesus was born on December 25, Mary's conception was 9 months earlier. In fact, Christian calendars celebrate the annunciation of the archangel Gabriel to Mary on March 25. Though the catholic Church does not have a liturgical feast for the conception of John the Baptist, the ancient Eastern Churches celebrate it solemnly between September 23rd and 25th, six months before the Annunciation to Mary.
However, this logical succession of dates from the conception of John had been based on unverifiable traditions until some decades ago, when the Dead Sea Scrolls were discovered. Professor Shemarjahu Talmon, using the texts found in the Essenes library of Qumran, was able to establish in which immemorial, unchanging chronological order the 24 priestly classes followed one another, and related this order to our Gregorian calendar.
Two from the Dead Sea Scrolls at their location in the Qumran Caves before being removed by archaeologists (photo Abraham Meir Habermann).