From the lyrics.
“And so it was that later
As the miller told his tale
That her face, at first just ghostly,
Turned a whiter shade of pale”
Is that a reference to the Canterbury Tales?
A recent thread addressing the song.
Thanks, scabpicker.
NP, wish I had more to say 
I had always assumed it was, until the thread that scabpicker linked. I’m slightly disillusioned to find out the truth…
“That is beautiful, so meaningful! How did you write it?”
Musician: “I was stoned out of my gourd.”
