Foundation created by the ruling classes (13)
I believe the answer is:
establishment
This clue is a double definition.
'foundation' is the first definition.
(I've seen this before)
'the ruling classes' is the second definition.
(I've seen this before)
'created by' is the link.
(Other definitions for establishment that I've seen before include "Action of setting up on a permanent basis" , "Those in power" , "Power-wielding class" , "Act of setting up" , "Foundation" .)