Is Christmas based on pagan celebrations? Is there a War On Christmas? Why do we have the decorations we do? What does it even mean to get into the spirit of Christmas? What follows starts 2,000 years ago; meander through the Middle Ages, Puritans, and your local Starbucks; and end up in your heart. I hope you enjoy the journey!
The date of Jesus’ birth is not known. Dionysius (1st century) is known for doing the historical math and arriving at a birth year around BC 12. Others disagreed. Generally, Jesus’ birth date is now placed around 4 BC, but there is nothing of theological or spiritual significance that hangs on this date. It was not a priority in the early church, and no writer of Scripture saw fit to include a date.
The early church associated birthday celebrations with the pagan gods. Early Christian writers (Irenaeus, 130–200; Tertullian, 155–240; Origen of Alexandria, 165–264) mocked Roman celebrations of birth anniversaries, dismissing them as “pagan” practices—a strong indication that Jesus’ birth was not marked with festivities at that place and time.Origen (c.185-c.254) said it would be wrong to honor Christ in the same way Pharaoh and Herod were honored. Tertullian did not list it as a Christian holiday for sure.
When Jesus’ birthdate was discussed, the date would have been figured out from a tradition that martyrs died on the same date they were conceived. If Jesus died on 14 Nisan (March 25), he was conceived on a March 25, which meant he was born on December 25 if the timing was perfect.
Hippolytus' Commentary on Daniel (AD 200) claimed either March or December 25 as the date for Jesus' birth; Clement thought March 25 as the date of Jesus conception, thus 9 months before his birth and death.
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THE ROMAN INTERLUDE: Did Christians Join A Pagan Holiday?
SATURNALIA: In the time that Jesus was born, Roman had been observing Saturnalia starting December 17 and generally lasting 6 days. It was a holiday in honor of Saturn, “the birthday of the unconquered sun,” and it was a party (to say the least) characterized by a lot of personal and societal chaos. It was a mix of good and bad for sure.
There seems to be little reason to think Christians chose December 25 to join or subvert a pagan holiday. The Jewish population from which Christianity emerged was quite good at establishing their own holidays, and their math was based on Jesus’ death date/conception date. Really, because the early church did not celebrate birthdays, the likelihood of Saturnalia influencing a Christmas celebration is small. The more likely candidate for potential overlap is the next one.
SOLIS INVICTI. “On December 25th, 274 AD, the Emperor Aurelian created a holiday called Dies Natalis Solis Invicti – the birthday of the Sun – officially elevating the Sun to the highest position among the gods.”  This would be a better candidate for the melding of Christian and pagan holidays, but by the time December 25 becomes a Christian celebration, Solas Invicti was largely more of a cultural festival than a religious one.  In fact, a Christian writer in 320 insisted there was a marked difference in intent: “We hold this day holy, not like the pagans because of the birth of the sun, but because of him who made it.”
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A Roman almanac from 336 that lists the death (and thus birth) dates of various Christian bishops and martyrs, the first date listed, December 25, is marked: natus Christus in Betleem Judeae: “Christ was born in Bethlehem of Judea. 
By AD 386, Chrysostom celebrated December 25th as Jesus’ birthday, preaching, "Without the birth of Christ there is no Baptism, no Passion, no Resurrection, no Ascension and no Pouring out of the Holy Spirit..."
Augustine (354-430 AD) wrote: “So then, let us celebrate the birthday of the Lord with all due festive gatherings.” 
In 389 St Gregory (one of the Four Fathers of the Greek Church) warned against 'feasting in excess, dancing and crowning the doors'.  Things were already getting a little rowdy.
The Feast of the Nativity spread to Egypt (in the 400s), England (in the 500s), Scandinavia by the 700s (we get the language of “Yule” and the tradition of Yule logs from them), and Russia by the 900s.
During the Middle Ages (400-1400) the church formally increased the focus on Jesus’ birth, but a lot of the informal celebration was not as focused. This is where one could argue that a Saturnalia-type of influence began to significantly overlap. Wikipedia’s article on Saturnalia actually has a really good article making some correlations.
From the mid-fourth century on, we do find Christians deliberately adapting and Christianizing pagan festivals. A famous proponent of this practice was Pope Gregory the Great, who, in a letter written in 601 C.E. to a Christian missionary in Britain, recommended that local pagan temples not be destroyed but be converted into churches, and that pagan festivals be celebrated as feasts of Christian martyrs. At this late point, Christmas may well have acquired some pagan trappings. But we don’t have evidence of Christians adopting pagan festivals in the third century, at which point dates for Christmas were established. 
One overlap was that the poor would go to the rich and demand their best food and drink, like a Christmas version of trick or treat. There was a significant economic Reason For The Season as Christmas became a time when the poor demanded that the rich unScrooge themselves for at least one holiday.
The Catholic Church had the first Midnight Mass on Christmas (“Christ’s Mass”) Eve 1039; it was a celebration that marked a transition from fasting to feasting.  As much as the Church formally focused on Jesus, Christmas was never fully able to avoid excess in all kinds of feasting once it got outside the confines of the church building.
In the 12th century, we find the first suggestion that Jesus’ birth was deliberately aligned with pagan feasts. A biblical commentator from Syria claimed the Christmas holiday was actually shifted from January 6 to December 25 to align with the Sol Invictus holiday. There is no reason to believe this is true, though I think it’s fair to say the raucous cultural celebrations had an influence on the informal celebrations of Christmas.
Reformers (beginning 1517) hit the holiday celebration issue pretty hard, which is understandable considering the partying that was going on informally and their reforming push for the Catholic Church.
In the 1640s, Puritan Separatists who ‘separated’ from the Church of England sailed across the pond and came to America, with no desire to continue the observation of Christmas practiced in England. (Christmas was a time of drunkenness, rioting and “misrule’, unfortunately, and the religious tension was, uh, strong).
When Oliver Cromwell and the Long Parliament took over England around that same time (1645), they vowed to rid England of decadence and, among other things, cancelled all Christian holidays except Sunday. They even changed the name of Christmas to “Christ-tide” to avoid the word “mass.”
The Puritans did NOT bring Christmas with them to what we now call the New England states. In fact, from 1659 to 1681, the celebration of Christmas was outlawed in Boston (you could be fined five shillings for exhibiting Christmas spirit). In the War on Christmas in the history of U.S. culture, the Puritans win hands down. On the other hand, John Smith reported that Christmas was enjoyed by all at Jamestown, which was settled by Anglicans, people who still were loyal to the Church of England.
Whatever Christmas momentum might have started in Jamestown faded for a while after the American Revolution (English customs were not popular, as you might imagine). Still, the Anglican South was for more hospitable to Christmas than the Puritan North.
Fast forward to the 1800s. Unemployment and poverty were high, and actual riots by the poor often occurred during Christmas. A policeman was killed trying to stop a fight between Catholics holding a Christmas Mass and Protestant fundamentalists trying to stop them.
“Christmas joined Sabbath observance, slavery, women’s rights, corruption, immorality, crime, drugs, prostitution, gambling and alcohol, as major moral issues that risked plunging the city and the nation into chaos during the early decades of the young republic. In fact, daily violence reached such proportions that in 1828 the city established its first professional police force following an especially violent Christmas riot. “
In 1819, Washington Irving wrote a book (The Sketchbook of Geoffrey Crayon, Gent) that was basically a series of stories/essays that featured an English squire who invited the peasants into his home for the holiday where the two groups mingled in friendship. To Irving, Christmas should be a peaceful, warm-hearted holiday that united people from every walk of life. He also wrote "Diederich Knickerbocker's History of New York," in which Sinterklaes rode through the skies in a horse and wagon and went down chimneys to deliver presents to children.  
Around that time (1843), Charles Dickens wrote A Christmas Carol, a novel which had a huge impact in both England the U.S. It prominently features not a conversion to celebrating Jesus, but a conversion to a spirit of generosity (Dickens himself likely saw this as a necessary outworking of honoring the birth of Jesus). “God bless us, everyone,” is experienced through the practical provision charity and generosity and the warmth of family.
The U.S. being the melting pot that it was, people began building traditions from all sorts of sources, [19, 20] Still, as late as 1855, Presbyterians, Baptists and Methodists did not celebrate Christmas, while Episcopalian, Catholic and German churches did.  Southern Baptists started moving in that direction after the Civil War ended in the 1860s.
In June 26, 1870, Christmas was officially declared a federal holiday (a number of states, especially from the Anglican tradition in the South, had already made it a state holiday).
Interestingly, by the mid 1900s, the main opposition to Christmas celebrations had been either within the church or between Christians and their Jewish spiritual cousins. The growing Jewish population in the U.S. found themselves very much at odds with a celebration of the birth of the Messiah, so they decided to join in attempts to secularize the holiday so it would be more like an American national holiday rather than a religious one. One of the main contributors was Irving Berlin (1888-1989), a Jewish immigrant whose family fled the pogroms in Russia. He composed the all-time Christmas favorite “White Christmas” in 1942. The wait for snow replaces any expectation of the arrival of the Messiah. 
CHRISTMAS CUSTOMS 
THE CHRISTMAS TREE: Pagans had long used trees as an accompaniment to their worship (the oak was a popular one). Christianity did not ban trees; it reframed the use. Around 700, the trees associated with pagan worship were replaced by the fir tree as symbol of Christianity (because of its triangle shape /the Trinity). The ‘ever green’ was also associated with eternal life.CHRISTMAS PRESENTS: a reminder of the gifts of the Magi, and of God’s gift of Jesus to us.
CANDY CANE: the shepherd’s crook of the Good Shepherd.
POINSEETTIAS: the star of Bethlehem.
WREATH: a symbol of true love, which never ceases.
HOLLY: a symbol of the crown of thorns worn by Christ on the cross.
BELLS: they stand for joy, and as a reminder that Jesus is the Great High Priest (Jewish priests had bells attached to the hem of their robes).
TREE BAUBLES OR BALLS: in early church calendars of saints, December 24th was Adam and Eve's day.  The Christmas tree became a symbol of the tree of Paradise, and people started decorating it with red apples. Originally the apples were a reminder of sin; they morphed into a symbol for the fruits of the Spirit.
LIGHTS: around 1500, Martin Luther brought a tree indoors and decorated it with candles in honor of Christ’s birth (indoor stars!).  Interesting side note: Thomas Edison (1847-1931) presented his first string of electric Christmas tree lights in 1880.  To advertise his new lights, Edison and his General Electric Company sent picture postcards to families in which strings of lights not only decorated the tree but were strung throughout the house. Since these indoor trees needed decorations, a businessman named Woolworth signed a monopoly agreement with the German manufacturers of glass ornaments which he marketed at his growing national chain of stores. The smaller ones sold for 5 cents and the larger ones for 10 cents, thus the origin of the 5 and 10 cent store. 
MISTLETOE (“dung twig”): In the Middle Ages in England, it was hung to ward off evil spirits and witches. In Scandinavia, it was a plant of peace. In Norse legend, it was a symbol that reminded them to protect life. In many cultures it was considered a cure-all medicine. The Catholic church banned it for a while because of how much the pagans loved it, but it’s easy to see how it blended into a celebration of a baby that would heal all nations and bring peace, and who died so we could live.
SAINT NICHOLAS/SANTA CLAUS The Catholic Church associated gift giving with Saint Nicholas, one of the bishops who convened the Council of Nicaea in 325. Legend says he became aware of some desperate needs in his congregation (a family selling their children into slavery, among other things), so he gave money, fruit, food, etc. 
In 1087, a group of sailors moved his bones to Italy and basically worshipped him. This group (a cult, really) was eventually adopted into German and Celtic pagan religions. These Celts worshipped Odin/Woden (from whom we get the word Wednesday), who had a long, white beard and rode a horse through the heavens. As these Celts converted into the Catholic Church, the church moved that horse ride through the heavens to December 25. St. Nicholas was the rider, not Woden. Problem solved.
In 1809, Washington Irving (remember him?) wrote a story  that featured a white bearded, flying-horse riding Saint Nicholas using his Dutch name, Santa Claus. 
An illustrator named Thomas Nast drew more than 2,000 cartoons of Santa for Harper’s Weekly during the mid-late 1800s. Nast added the North Pole, a workshop with elves and the good/bad list.  In 1931, Coca Cola insisted that Santa, who was the face of their new campaign, be in a bright, Coca Cola red suit. 
Santa Claus: A Christian bishop from the Council of Nicaea filtered through Celtic gods, Dutch culture and American cartoons, and brought to you by Coca-Cola.
ADVENT (ARRIVAL) Advent as a season had been around a long time, but the first printed Advent calendar appeared in Germany in the early 1900s. During WWII, the Nazi Advent calendar included swastikas and took traditional pictures (like Mary, Joseph, and the baby Jesus) and retold them (this was a woodcutter, a soldier, and a king who get lost, then meet a woman whose baby has wise advice).
After the war, commercial production of Christian Advent calendars ramped up. Between that and the GIs who sent them home to their families in the States, it caught on here. 
First, I think we need to relax with our concern about the War on Christmas. The early church didn’t celebrate for at least 250 years. For a lot of history, the birth of Christ was probably dishonored by how Christians informally celebrated. 200 years ago, if Starbucks had existed, and if they had put out cups promoting Christmas, we would have boycotted them. 200 years from now, that might be the case again. This holiday has been full of tensions among Christians over how to properly celebrate. The celebratory side has run the gamut from profoundly holy to amazingly vulgar, and finding a way to celebrate the birth of Jesus in a way that continually elevates Christ rather than money and over-indulgence has historically proven difficult.
Second, I can’t imagine Jesus or the early church encouraging Christians to be offended that those outside the church don’t embrace this time as a celebration of Jesus like we do. We, of all people, ought to be showing what good will on earth looks like. If Starbucks wants to print a cup that says “Happy Saturnalia,” and businesses require employees to say “Happy Humbug,” that’s their call. They don’t worship Jesus like I do; I don’t expect them to respond to his birth like I do.
To Christians, Christmas is a celebration of the birth of The King, and as such is loaded with implications of allegiance. I would expect this space to be a spiritual battleground of sorts in the sense that our allegiances and our hearts are tested. It’s unsettling to the leaders of earthly empires and spiritual principalities and powers that there is King to whom millions give their highest allegiance. The celebration of Christmas will always be joyfully tumultuous in the world.
Third, probably our biggest challenge as Christians is to make sure that our Christmas celebrations do not settle into the secularized version that focuses merely on giving gifts, feeling good and warm, and offering vague sentiments about peace and happiness.
I am not opposed to those things – I like all of those things, in fact – but I suspect we are far more likely to miss the heart of Christmas when our hearts are distracted rather than when a courthouse lawn doesn’t have a crèche or a school says “holiday break” instead of “Christmas break.” Donald Heinz  notes we must be careful not to focus
“…on all the materials that claim to be good instead of on the Good that claims to be material [in Jesus].”
The other things can be a great and meaningful contribution – our gift-giving reminds us of the One who gave his life; our blessing others overflows from how God has blessed us; our feasting mimics the love feasts of the early church and points toward Revelation's Marriage Supper of the Lamb – but for Christians, those find their meaning, and the eternal hope, peace and joy we celebrate at Christmas - through Jesus.
 He received a tradition that the Roman emperor Augustus reigned 43 years and was followed by the emperor Tiberius. Jesus was 30 in the 15th year of Tiberius’ reign (Luke 3), which meant he lived 15 years under Augustus (so, born in the 28th year of Augustus reign).
 An anonymous document from North Africa placed Jesus birth on March 28; Clement (bishop of Alexandria) thought Jesus was born on November 18.
 In 1821, an American children's book called "The Children's Friend" changed Santa's horse and wagon to a reindeer and sleigh.
 For example, German immigrants brought their tradition of putting lights, sweets and toys on the branches of evergreen trees placed in their homes.
 His family left Russia 3 years before the setting of Fiddler On The Roof. The only memory he would talk about was watching his family’s home burn to the ground.
 In Philip Roth’s novel Operation Shylock (1993), Roth boasts that Irving “de-Christs” Christmas. “He turns Christmas into a holiday about snow—he turns their religion into schlock (Yiddish for something cheap, shoddy, or inferior)… If supplanting Jesus Christ with snow can enable my people to cozy up to Christmas, then let it snow, let it snow, let it snow.” https://touroscholar.touro.edu/cgi/viewcontent.cgi?article=1181&context=nyscas_pubs
 As for nativity scenes…the Gospels do not mention there being any oxen, donkeys, camels or Magi at the manger. The Gospel of Pseudo-Matthew, a medieval text, has heavily influenced the images in our heads as well as our Christmas songs.
Tradition about the Magi built from some assumptions from OT passages (Isaiah 1:2-3; 60:3, 6, 10-11;Psalm 72:10). An early church leader named Origen decided that Genesis 22 had something to say about the Magi, so he set the number at 3. Don’t ask me to explain why.
 A story is told that, one night before Christmas, he was walking through the forest and looked up to see the stars shining through the tree branches. It was so beautiful, that he went home and told his children that it reminded him of Jesus, who left the stars of heaven to come to earth at Christmas.
 My Grandma was 6 years old when Thomas Edison died.
A satire of Dutch culture called Knickerbocker History.
 In 1822, we got this iconic poem (based on Irving’s writing): “Twas the night before Christmas… in the hope that Saint Nicholas soon would be there…”
 “During the American Civil War, Nast mobilized Santa as a representation of American nationalism, often portraying him wearing a blue outfit with stars distributing gifts to Union soldiers and referring to him as ‘Santa Claus.’” https://touroscholar.touro.edu/cgi/viewcontent.cgi?article=1181&context=nyscas_pubs
 The first chocolate Advent calendar appeared in 1958; by 1971, Cadbury was all over it. Advent is now a chocolate cash cow.
 I am quoting from a review of his book, Christmas: Festival Of Incarnation