Answer:
You may have heard it a million times, but the main purpose of Christmas is celebrate Jesus' birthday. Even though I've heard he actually wasn't born on December 25 (they said it was June or July). Whatever day he may have been born on, that's the original purpose for Christmas. Just my two cents.
Another answer:
The XMAS was a result of persecutions of Christians in early in 2nd and 3rd century AD when it was illegal to worship or to even write the word Christ.