He was of remarkable greatness (5)
I believe the answer is:
scott
'he' is the definition.
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for scott that I've seen before include "Sir Walter --, writer" , "Novelist Sir Walter" , "one wanting to explore?" , "Sir Peter -----, ornithologist son of a great explorer" , "Ivanhoe's creator" .)