Wrote of being confined (6)
I believe the answer is:
penned
This clue is a double definition.
'wrote' is the first definition.
('pen' can be a synonym of 'write')
'being confined' is the second definition.
(synonyms)
'of' acts as a link.
(Other definitions for penned that I've seen before include "Wrote; enclosed" , "Caged, wrote" , "Confined; written" , "in Reading Gaol, perhaps" , "in captivity" .)