Manage lines in Old English (7)
I believe the answer is:
oversee
'manage' is the definition.
(I've seen this before)
'lines in old english' is the wordplay.
'lines' becomes 'verse' (I've seen this before).
'in' indicates putting letters inside.
'old english' becomes 'oe'.
'verse' put within 'oe' is 'OVERSEE'.
(Other definitions for oversee that I've seen before include "Keep a check on" , "take charge" , "Inspect" , "Supervise like ganger" , "Supervise, control" .)