Place of retreat three magi rebuilt (9)
I believe the answer is:
hermitage
'place of retreat' is the definition.
(I've seen this before)
'three magi rebuilt' is the wordplay.
'rebuilt' indicates anagramming the letters.
'three'+'magi'='threemagi'
'threemagi' is an anagram of 'HERMITAGE'.
(Other definitions for hermitage that I've seen before include "Place of retreat" , "Recluse's abode" , "accommodation for one" , "Home of a recluse" , "art museum" .)