December 25th was the day of the Roman cult of Sol Invictus, the undefeated sun. The Philocalian calendar of AD 354 is the earliest literary reference both of this and of Jesus’ birthday. Many people accept that there is a connection between the two, not least because the Bible likens Jesus to the sun. Christian celebration on the 25th was well established following the outlawing of Paganism by Theodosius after the year 381. In the subsequent centuries, many traditional midwinter customs such as feasting, gift giving and bringing evergreens into the house became associated with it. The Puritans couldn’t decide whether to hate this because it was Catholic or because it was Pagan. In any case, they tried to ban it both in revolutionary England and in their religious republic in Massachusetts. Misrule was always present, but in the 19th Century, wassailing started to annoy the wealthy, who promoted a sentimental process of domestication. In recent years some people have behaved as if there were something offensive about the religious elements of our traditional midwinter celebration, while others even claim to believe that there is a campaign to do away with it altogether; I can only hope you won’t mind if I wish you – a very merry Christmas.
Bull-Killer, Sun Lord. "Foreign religions grew rapidly in the 1st-century A.D. Roman Empire, including worship of Jesus Christ, the Egyptian goddess Isis, and an eastern sun god, Mithras."