Merry Christmas Origin and History These days, it's common practice to wish "Merry Christmas" to one another around the 25th of December, the day of Christmas.  The origin of this practice is a little obscure. However, it's believed that an English admiral first used the term Merry Christmas in an informal letter, way back in 1699. In the same era, the phrase was used in non-relgious Christmas song 'We wish you a Merry Christmas', which is still popular today. In 1843, Charles Dickens used the same phrase in "A Christmas Carol." also in 1843 the first ever Christmas Card was produced…