Norway's patron saint (4)
'norway's patron saint' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for olaf that I've seen before include "King and patron saint of Norway" , "King --, cantata by Elgar" , "Name of five Norwegian kings" , "Man's name; foal (anag.)" , "Name of five kings of Norway" .)
(Other definitions for olav that I've seen before include "Norwegian name (of its saints and kings)" , "king of yesteryear" , "Name of kings of Norway" .)