The meaning behind the familiar 12 Days of Christmas carol may be closely tied with religious teachings, rather than a marketing invention, according to research by historical theologian Bronwen Neil.
To many who have heard dozens of adaptations, the song seems to bring together a random bunch of animals and people like "eight maids a-milking" and "11 pipers piping."
But Dr Neil, from the Australian Catholic University, says the song may have been in fact a secret teaching tool for Catholics during the 18th and 19th century.
While the original songwriter is unknown, the English version first appeared in a children's book in 1780.
Dr Neil said that in 1979, Canadian hymnologist Hugh McKellar floated the idea that the song had a secret code — a theory she said "had merit" but could not be proven.
"The carol was a secret catechism for Catholics in England when Catholicism was persecuted during the war of religions from Henry the VIII to 1829," Dr Neil told 702 ABC Sydney.
"This song gave them a chance to teach their kids knowledge of the saints and doctrine in a secret code when the Protestants were cracking down on the Catholics."
The true 12 days of Christmas varies across some 50 religious denominations, but the Catholic version has the Christmas season starting on December 25 and concluding with the Epiphany.
Each day represents the celebration of a martyr, saint, or a feast connected with Jesus' birth.
Boxing Day for example, considered day two of Christmas, is the Feast of Saint Stephen, a deacon who gave present boxes to the poor.
"The feast wraps up on January 6, which is the revelation of Christ as the saviour and son of God to the world," Dr Neil explained.
"On that day, the Orthodox celebrate the baptism of Christ and the Catholics celebrate the arrival of the Magi — the three wise men with their presents [and] it's in their memory that we give presents."
According to Ms Neil, each item in the 12 Days Of Christmas song was a metaphor for a bible story.