Christmas is a Christian holiday that refers to the birth of Jesus who is the Son of God.
During the past (in the early years of Christianity) Easter was the holiday. That means that the Birth of Jesus was not celebrated. Then the Church officials made up their mind to declare the birth of Jesus as a Holiday.
But there is no evidence to say that Jesus was born in such a year. But there is an evidence that he was born in spring. So with this the Pope Julius chose the date as December 25th. In order to absorb the traditions of the pagan Saturnalia festival, it is believed that the church chose this date. And then slowly by the end of 8th century the spirit and celebration of Christmas had spread to Scandinavia. According to the Greek and Russian orthodox churches, Christmas is celebrated 13 days after December 25th. This is referred to as the “Epiphany” or the Three Kings Day. It is believed that the 3 wise men found Jesus in the manger.
Here there are some flamboyant and retina ready Christmas GIFs for all.