1066 invaders (7)
I believe the answer is:
normans
'1066 invaders' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for normans that I've seen before include "Some Frenchmen" , "French folk" , "Our last successful invaders" , "Invaders in 1066" , "belonging to Greg the golfer?" .)