Proper Holiday Greeting........

i am not sure about this but i think the word merry did not come from mary.

honestly i have no clue but a lot of people say happy christmas too

just had a look on google and found this:

Though Christmas has been celebrated since the 4th century AD, the first known usage of any Christmastime greeting, "Merry Christmas and a Happy New Year" (thus incorporating two greetings) was in an informal letter written by an English admiral in 1699. The same phrase appeared in the first Christmas card, produced in 19th century England.

The then relatively new term "Merry Christmas" figured prominently in Charles Dickens' A Christmas Carol in 1843. The cynical Ebenezer Scrooge rudely deflects the friendly greeting and broods on the foolishness of those who utter it. "If I could work my will," says Scrooge, "every idiot who goes about with 'Merry Christmas' on his lips, should be boiled with his own pudding." After the Spirits of Christmas effect his transformation, he is able to heartily exchange the wish with all he meets. The continued popularity of A Christmas Carol and the Victorian era Christmas traditions it typifies have led some to credit Dickens with popularizing, or even originating, the phrase "Merry Christmas"[1].