Be responsible for poetry in Old English (7)
I believe the answer is:
oversee
'be responsible for' is the definition.
(I've seen this before)
'poetry in old english' is the wordplay.
'poetry' becomes 'verse' ('verse' can be a synonym of 'poetry').
'in' is an insertion indicator.
'old english' becomes 'oe'.
'verse' put within 'oe' is 'OVERSEE'.
(Other definitions for oversee that I've seen before include "survey" , "Administer" , "risk eyestrain?" , "guide" , "Supervise officially" .)