Christians around the world celebrate Dec. 25 as the birth of Jesus. But as many gather to exchange gifts, sing carols and marvel at Nativity scenes and Christmas trees, the story behind Jesus' birthday is more complicated than some may think.
Scholars of history and the Bible have tackled the issue in the past: When was Jesus actually born? Here are a couple of points to consider.
What does the Bible say?
The Gospel of Luke tells us that Jesus was born at a time when shepherds were watching their flocks at night. This clue tells us that Jesus' birthday was not in the winter, since shepherds only look after their sheep during the spring. If the birth of Jesus had happened during the winter, the sheep would have been corralled.
The Gospel of Luke also notes that Jesus' parents came to Bethlehem to register in a Roman census (Luke 2:1-4). According to the United Church of God, taking a census would have been difficult in December because of harsh winter conditions.
So when was Jesus born? Some Bible experts say that Jesus might have been born by the end of September, based on the conception and birth of John the Baptist.
If we factor in the year in which Jesus was born, things become even more complicated. The Gospels of Matthew and Luke both mention that Jesus' birth took place when Herod the Great, a Roman king, was still alive. However, their chronicles differ from each other by 10 years, according to Mark Goodacre, a professor in the Duke University Department of Religion who spoke to Time.
Luke says that Jesus began preaching when he reached 30, which would take his birth year back to 1 B.C.E. But according to Goodacre, Luke may have miscalculated the death of Herod, so Jesus could have been born in 4 B.C.E.
Is Christmas a pagan tradition?
Although Jesus' birth has long been commemorated on Dec. 25, Christians didn't celebrate the birth of Jesus in the first two Christian centuries — or at least, there is no record of it. A Roman almanac documented the earliest known celebration of Christmas by the church of Rome in 336 A.D., leading researchers to believe that Christmas originated as a Christian substitute for pagan festivities of the winter solstice. Every December, Romans honored Saturn, the god of agriculture, during a festival called Saturnalia.
The conversion of Roman emperor Constantine I to Christianity in the year 312 was pivotal for the incorporation of winter solstice celebrations so that the emperor's subjects could easily adopt Christianity. To explain Jesus' birth on Dec. 25, church leaders argued that God conceived Jesus on the spring equinox, when the world was allegedly created. The Virgin Mary, pregnant with Jesus, would have given birth nine months later on the winter solstice. This is the description of the Christ's Nativity celebration, which spread across Christian churches.
Over time, some Christians began accepting Dec. 25 as Jesus' birthday, while other pagan elements were being incorporated into the tradition of Christmas — like the use of Christmas trees, which predates the birth of Christianity.
Despite scholarly research regarding Christmas Day, most experts are still unsure about the true date of Christ's birth. Consequently, Christians will choose to either embrace or reject the celebration as it draws near every single year. But Slate's Andrew Santella writes that believers should not worry about Christmas' pagan roots: "If the church repurposed the old solstice feasts, it only goes to show its power to bend the broader culture to its pastoral purpose."