There are references to 'mery' Christmas from the 1500s and the carol God Rest You Merry, Gentlemen was first published in 1833. But the two key events which established Merry Christmas as one of the most commonly used expressions in the English language both occurred in 1843.
The first was the publication of a commercially produced Christmas card with slogan 'Merry Christmas'. Exchanging cards became one of the 'new traditions' of Christmas introduced by the Victorians. Merry Christmas was the default message - as it still is today
In this and other respects Dickens can be said to have invented the modern, secular Christmas festival - see here.
Did Dickens invent the modern Christmas?
Fred & Rita: Christmas Ghost Story (playscript/worksheet)
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A Christmas Carol Teaching Pack
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