New Rochelle college (4)
I believe the answer is:
iona
'new rochelle college' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for iona that I've seen before include "Isle of the Inner Hebrides, made famous by St Columba" , "island off Scotland" , "Inner Hebridean island" , "St Columba's island of the Inner Hebrides" , "Scottish island from where Christianity spread in 563 AD" .)