God Rest Ye Merry, Gentlemen was an ancient Earth Christmas carol. It was this song that was being played by a group of robotic Santas prior to attacking Rose Tyler and Mickey Smith on Earth. (DW: The Christmas Invasion) A group of children were also singing this song when the Doctor arrived in London on Christmas Eve 1851, just before his encounter with the Cybermen. (DW: The Next Doctor) The song was also heard played by a brass band shortly before the tenth Doctor regenerated (DW: The End of Time)
The melody of the carol was the same as that of the "Venusian lullaby" occasionally used by the Third Doctor to lull his foes into a state of tranquility. (DW: The Dæmons, The Curse of Peladon and MA: Venusian Lullaby)
