Greg Lake also wrote one of the Christmas songs that I look forward to hearing every Holiday Season, namely: “I Believe in Father Christmas”.
I did not hear that song in its entirety until years later; I thought it was quite pretty. When I finally heard all the lyrics, I no longer cared for it.
(Though it is beautifully performed.)
I much prefer "Chris Squire's Swiss Choir" if I want Christmas music from a prog-rocker. A FReeper turned me on to that album a few years back.