In an effort to convert the people of those cultures, the church appropriated pagan holidays and superimposed saints days and other religious events over them. Perhaps its most brilliant strategy was to establish December 25th as Christ’s birthday—Christ mass—when, according to biblical accounts, Jesus was born in the spring.
This was the time of year the Romans celebrated their god Saturn in a festival called Saturnalia. It ran from December 17 to December 23rd.
were festooned with garlands and candles. The senate closed, no criminals were executed and students enjoyed a holiday from school. Saturnalia was marked by the making and giving of presents, the sharing of food and drink, and a great deal of merry making. Roles were reversed; slaves pretended to be masters and masters had to serve their slaves. Temples
More important, between 274 and 390 A.D., the Romans worshipped the sun god Sol Invictus. They celebrated December 25th as his Dies Natalis Solis Invicti—birthday of the unconquered sun.
The Vikings celebrated the twelve-day winter festival of Jōl (Yule) around the winter solstice in late December. Jōl means “wheel,” which is how the Vikings perceived the seasons.
They believed the winter solstice was the height of their father god Odin’s wild hunt across the skies on his eight-legged horse Sleipnir, a hunt which began on the Autumnal Equinox and ended at Beltane. Father Odin had a different aspect for every season of the year. In December, he was an elderly man in a long cloak with a flowing white beard. Norsemen believed the veil between this world and the next was thinnest at the winter solstice. The spirits of their ancestors walked abroad.
For the Celts, this was the time of year when the Oak King of summer and Holly King of winter fought for dominance. And while they battled, the sun stood still. (solstice is derived from the Latin word sol, which means sun, and sistere, which means to stand still.) They built stone circles and mounds to precisely mark when the winter solstice occurred. The Celts fashioned wreaths and garlands from sacred evergreen plants (ivy of the Oak King, holly of the Holly King, and magical mistletoe) and decorated their homes to remind themselves that life would return to their forests and fields in the spring. They rang bells and sang songs to drive away evil spirits.
It is important to note that, for most pagan cultures, the winter celebration lasted longer than a single day. It is therefore no accident the church established Christmastide/Yuletide as running from Christmas Eve until Twelfth Night (Epiphany) on Jan 6th.