One featured in theatre area for long period in the past (5,3)
I believe the answer is:
stone age
'long period in the past' is the definition.
(historical period)
'one featured in theatre area' is the wordplay.
'featured in' is an insertion indicator.
'theatre area' becomes 'stage' (stage in a theatre).
'one' put into 'stage' is 'STONE-AGE'.
'for' acts as a link.
(Other definitions for stone age that I've seen before include "Primitive period" , "Go, senate to ancient era before metal was discovered" , "Earliest known period of human culture" , "Early epoch when man used pre-metal tools" , "Early period" .)