Anglo-Saxon kingdom (5)
I believe the answer is:
essex
'anglo-saxon kingdom' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for essex that I've seen before include "Home county" , "County NE of London" , "Favourite of Elizabeth I" , "R. Devereux, Earl of -" , "Stereotypical promiscuous and materialistic young woman (from Colchester?)" .)