The fruits of one's studies of history? (5)
I believe the answer is:
dates
'the fruits' is the definition.
(date is a kind of fruit)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for dates that I've seen before include "Takes out" , "Particular times" , "Palm fruit" , "Goes steady" , "Fruit - shows its age" .)