Archeologists say they have traced the origins of the first Christmas to be celebrated on 25 December, 300 years before the birth of Christ. The original event marked the consecration of the ancient world's largest sun god statue, the 34m tall, 200 ton Colossus of Rhodes. It has long been known that December 25 was not the real date of Christ's birth and that the decision to turn it into Jesus's birthday was made by Constantine, the Roman Emperor, in the early 4th century AD. But experts believe the origins of that decision go back to 283 BC, when, in Rhodes, the winter solstice occurred at about sunrise on December 25.
The event was preserved by academics on Rhodes or in Alexandria, and seems to have been passed to Caesar by the Hellenistic Egyptian scientists, who advised him on his calendrical reforms. The date was chosen because the emperor seems to have believed that the Roman sun god and Christ were virtually one and the same, and the sun's birthday had been decreed as December 25 some 50 years earlier by one of Constantine's predecessors, the Emperor Aurelian. He, in turn, seems to have chosen 25 December because, ever since Julius Caesar's calendar reforms of 46 BC, that date had been fixed as the official winter solstice, even though the real date for the solstice in Caesar's time was December 23.
Independent.co.uk December 23, 2003