“God Rest Ye Merry Gentlemen” is one of the oldest existing Christmas carols. It dates back to the 1500s and earlier. This English carol has undergone many changes over the years.
In the 15th Century, church music was typically sung in Latin and was dark and rather somber. Consequentially, most church goers did not like the religious songs of the period. So, the faithful counteracted this tone by singing more uplifting songs in the streets.