E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Shorne (Sir John) or Master John Shorne,
well known for his feat of conjuring the devil into a boot. He was one of the uncanonised saints, and was prayed to in cases of ague. It seems that he was a devout man, and rector of North Marston, in Buckinghamshire, at the close of the thirteenth century. He blessed a well, which became the resort of multitudes and brought in a yearly revenue of some £500.
To Maister John Shorne, that blessed man borne,
For the ague to him we apply.
Which juggleth with a bote; I beschrewe his herte rote