Greta led father to become a maker of history (6,3,5)
I believe the answer is:
alfred the great
'a maker of history' is the definition.
I can't judge whether this definition defines the answer.
'greta led father to become' is the wordplay.
'to become' is an anagram indicator.
'greta'+'led'+'father'='gretaledfather'
'gretaledfather' with letters rearranged gives 'ALFRED THE GREAT'.
Can you help me to learn more?
(Other definitions for alfred the great that I've seen before include "Resistance leader" , "One who was crowned" , "King of Wessex from 871" , "monarch - with 23a" .)