Methodism's founder (6)
I believe the answer is:
'methodism's founder' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for wesley that I've seen before include "John, C eighteen Methodism founder" , "church founder" , "Founder of Methodism, d. 1891" , "John --, English preacher" , "Samuel Sebastian ---, composer" .)