Jesus was a Sun King (maybe like Mithras of Persia and Osiris of Egypt before him). You can tell by the way he is usually depicted with a halo of sun rays shining out from around his head. He is the latest in a long line of symbols of our sun worship that is many thousands of years old. The most important date in the solar worship calendar is the winter solstice: usually 21st December. This is when the sun 'dies' and is soon 'born again'. It is when its midday zenith (its highest point in the sky) stops descending and starts ascending. The rate of descent/ascent for a few days around the solstice is so slow that it is imperceptible to the naked eye. Not until telescopes were perfected by Galileo in the seventeenth century could astronomers see the infinitesimal changes in the sun's zenith either side of the solstice. Before that they had to work it out logically as Ptolemy did in ancient Greece by recording the sun's zenith through December and January and calculating the time of the solstice after the event. For thousands of years people saw the sun reach its lowest ebb and 'die' until, on the third day, it slowly began its re-ascent towards the summer solstice, bringing with it the promise of new life, another spring and another summer. They created the myth of the sun resurrecting itself on the third day.
Most people today know that the Christian church took over the pagan rebirth festivals of Yule and Easter and incorporated aspects that they couldn't erase. One important detail, mentioned several times in the Gospels and featured in the Eucharist or Mass, is how Jesus’ death is followed by his resurrection on the third day. Although Christianity has woven the myth of the resurrection on the third day into the rebirth festival of Easter rather than the birth festival of Christmas, it is nevertheless an example of Christianity building its myth on the ancient sun-worshipers' meaning. The Meaning of Christmas and of Yule before it is that, even in the darkest time, there is hope for the future.
As the Beatles said, "Here comes the Sun King, everybody’s laughing, everybody’s happy ... "