As we prepare to celebrate Christmas, it seems fitting to consider the centuries of traditions and beliefs that have shaped our holiday season. In the simplest terms, Christmas—an abbreviated version of “Christ’s Mass”—emerged from the early Christian church as a commemoration of the birth of Christ. The earliest records of such a celebration date back to the 2 nd century, but the customs that shape our holiday today emerged over the course of several hundred years. The selection of December 25 th as the official day of celebration was the product of much debate and research, and wasn’t agreed upon in the church until the 4 th century. Prior to this, some regions celebrated on January 6 th to commemorate the baptism of Christ (by John the Baptist) rather than the birth. December 25 th was selected because it was exactly nine months after March 25 th , which was widely believed to be the date of Christ’s conception. This was based on the date of Gabriel’s appearance to Zech...