Christmas as it is celebrated today did not start out looking anything like the modern holiday, and this History Channel production traces how it got there. It opens with the Roman Empire, where midwinter festivals like Saturnalia and the feast of Sol Invictus gave the early church a date and a set of customs to absorb once Christianity took hold, a Christianization process the film treats as central rather than incidental. From there it follows individual traditions forward: the evergreen tree, borrowed from older winter rites long before it held ornaments, and gift-giving, which shifts across centuries from religious observance to the commercial ritual familiar now. Expert interviews and archival footage carry most of the argument, backed by historical reenactments that put faces on customs otherwise known only from written sources. The film's case is that almost nothing about Christmas is fixed or original, every piece of it, tree, gifts, even the date, arrived by accretion from older, often pagan practices that got folded into a Christian holiday over roughly two thousand years.