Today, many (but not all) Christians celebrate Christmas on Dec. 25. But given that the birth date of Jesus Christ is not known with certainty, why was this day selected?
There are two major theories as to why Christmas is celebrated on Dec. 25. One, sometimes called the "history of religion" hypothesis, suggests that Christmas supplanted one or more pagan holidays. The other theory, often called the "computation" or "calculation" hypothesis, suggests that early Christians used some form of calculation to arrive at Dec. 25 as Jesus' birthday.
