Despite the current belief that using the term "X-Mas" is some sort of modern attempt at removing Christ from Christmas, its use actually goes back centuries. In fact, the letter X was commonly used as an abbreviation for Christ going back to the earliest days of Christianity; quite possibly because early adherents feared being identified as Christians and subjected to persecution.
Additionally, many have interpreted the prohibition against graven images found in the Old Testament to apply to textual representations of God. While most Christian adherents had stopped strictly interpreting the prohibitions against graven images, others continued to avoid textual use of Christ's name, therefore using X-Mas instead.
