I have recently seen a fellow called John Barleycorn mentioned in a couple of articles on beer. I had never heard of this person before and have now learned that John Barleycorn is an old English folk song and the character is a personfication of the barley grain and alcoholic drinks made from it. It can also have some pagan metaphorical intepretations.
Wikipedia has a piece here.
The music and lyrics are here.
and you can see and hear Traffic performing the song here.
and an excellent article on pagan pub names here.
So now you know. I drink a toast to John Barleycorn.