A container historic in building (7)
I believe the answer is:
holdall
'a container' is the definition.
(holdall is a kind of container)
'historic in building' is the wordplay.
'historic' becomes 'old'.
'in' is an insertion indicator.
'building' becomes 'hall' (hall is a kind of building**).
'old' going within 'hall' is 'HOLDALL'.
(Other definitions for holdall that I've seen before include "Large bag (no need for another?)" , "A large soft travelling bag - stuff everything in" , "Big bag" , "Bag (contents unlimited?)" , "Handled bag" .)