Manage poem in Old English (7)
I believe the answer is:
oversee
'manage' is the definition.
(I've seen this before)
'poem in old english' is the wordplay.
'poem' becomes 'verse' (verse is a kind of poem).
'in' is an insertion indicator.
'old english' becomes 'oe'.
'verse' inserted into 'oe' is 'OVERSEE'.
(Other definitions for oversee that I've seen before include "guide" , "Invigilate" , "Act as tutor" , "Keep a check on" , "take charge" .)