"A feast was
established in memory of this event [Christ's birth] in the
fourth century. In the fifth century the Western Church
ordered it to be celebrated forever on the day of the old Roman
feast of the birth of Sol, as no certain knowledge of the day of
Christ's birth existed."
- Christmas, Encyclopedia Americana (1944
"in [C.E.] 354,
Bishop Liberius of Rome ordered the people to celebrate
on December 25. He probably chose this date because the
people of Rome already observed it as the Feast of Saturn,
celebrating the birthday of the sun. Christians honored
Christ in-stead of Saturn, as the Light of the world," -
Christmas,The World Book Encyclopedia
(1962), p. 416.