The Corpus Christi carol

He bore him up, he bore him down, 

He bore him into an orchard brown. 

(Chorus) 

Lully, lullay, lully, lullay! 

The falcon has borne my make away. 

And in that hall there standeth a bed: 

It was hanged with gold so red; 

(Chorus) 

And on that bed there lieth a knight, 

His woundis bledyng day and night; 

(Chorus) 

And by that side there kneleth a may, 

And she wepeth both night and day; 

(Chorus)

And by that bed there standeth a stone, 

“Corpus Christi” written thereon.

(Chorus)

Key: "make" = "mate"; "may" = "maid"; "Corpus Christi" = "body of Christ"

There are many variants of title and lyrics, and even more of the melody.

But this is the tune I regard as definitive (although the performance is only adequate IMO - I can't find any better online). 

It is composed in the Doric/ Dorian Mode, which runs from D to D on the white notes of a piano; and is characterized by a minor third and a flattened seventh (no "leading note"). This lends a suitably "medieval" quality to the ancient song. 

This "carol" (it isn't really a carol) is very mysterious in its subject matter; seeming like an imaginary journey of initiation as we are led from scene to scene to a climatic revelation - none of which scenes are explained, and all of which seem "symbolic" in some way. 

Some ideas about the poem are that it is to do with a slain knight and his betrothed, the Holy Grail and the Fisher King; or Mary and Jesus (maybe the Blessed Virgin Mary, or perhaps Mary Magdalene) - or perhaps all of these at the same time.