Those from royal house built in Stroud (6)
I believe the answer is:
tudors
'those from royal house' is the definition.
'built in stroud' is the wordplay.
'built in' indicates anagramming the letters (the answer can be built from the letters).
'stroud' anagrammed gives 'TUDORS'.
(Other definitions for tudors that I've seen before include "Royal family" , "Members of a house" , "English monarchs from Henry VII to Elizabeth I" , "Royalty" , "English dynasty in the 16th century" .)