'X' mas ???

Just wondering...I'm not being narrow-minded or religious, but why X'mas?
Ever wondered why?
I've seen it all over the place, even some churches use it on their brochures.
I've asked around, and here are some answers i got.

-'Christ'mas is too long a word to fit in anywhere, so 'Christ' is shortened to just an 'X'. The 'X' bearing the sign of a cross...or so they say...u think so?
-'Christ' is a offensive to some people, so in order to censor the reason for the season, while still enjoying the season, they kinda cut out 'Christ', and dropped an 'X' in there. so, 'X' mas.

I don't really know exactly, but I'll let you figure it out for yourself. But think again before you put an 'X' on any card or anywhere else...