'Merry Christmas Baby' has got to be one of the most versatile holiday songs out there. Written by Lou Baxter and Johnny Moore in 1947, it's been covered by everyone from Chuck Berry to Otis Redding to Jessica Simpson.

It was, and remains, credited to Lou Baxter and Johnny Moore. But it was the performance of Charles Brown, the Three Blazers' pianist and vocalist, that defined the song - and he insisted that he wrote it, too.

"Merry Christmas Baby" is an R&B Christmas standard credited to Lou Baxter and Johnny Moore. In 1947, Johnny Moore's Three Blazers recorded the tune, featuring vocals and piano by Charles Brown.

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The reason is based on what the language signifies -- 'happy' is an emotion, while 'merry' is a behaviour. Moreover, the bishop John Fisher in a letter to Henry VIII's chief minister Thomas Cromwell wished "Merry Christmas".

But "Merry Christmas" has been used since at least 1534. A dated letter from bishop John Fisher to Henry VIII's chief minister Thomas Cromwell reveals as much. The English carol, "We Wish You a Merry Christmas," which was introduced in the 1500s, also uses the popular phrase.

Early music Music associated with Christmas is thought to have its origins in 4th-century Rome, in Latin-language hymns such as Veni redemptor gentium. By the 13th century, under the influence of Francis of Assisi, the tradition of popular Christmas songs in regional native languages developed.

Historians and linguists can't pinpoint for sure exactly why we tend to use Merry Christmas. The greeting dates back to at least 1534 in London, when it was written in a letter sent to Henry VIII's chief minister Thomas Cromwell from bishop John Fisher.

More and more slow, solemn hymns started to emerge in the fourth century, and by the 12th, songs referring to Nativity themes and creatures had emerged. According to Oxford Dictionaries, one of the oldest printed carols is the 'Boar's Head Carol', which dates from 1521.

When was the first carol and where? Scholars credit the world's oldest Christmas hymn-song to the 4th century in France and written by St. Hilary of Poitier (c310-367).

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