One who wrote of love endlessly, in detail at first (4)
I believe the answer is:
ovid
'one who wrote' is the definition.
(Ovid was a Roman poet)
'love endlessly in detail at first' is the wordplay.
'endlessly' indicates the central letters (the ends of the words are removed).
'at first' indicates taking the first letters.
The middle of 'love' is 'ov'.
The first letters of 'in detail' is 'id'.
'ov'+'id'='OVID'
'of' is the link.
(Other definitions for ovid that I've seen before include "Writer" , "Classical poet" , "Void for a Latin poet" , "Roman love poet" , "Roman poet (Metamorphoses)" .)