Complex sentence: Remoter land was granted to lords who were rewarded for the greater effort of subduing the natives with a greater autonomy; their grants specified vague territorial limits within which they were permitted to administer as much land as they could conquer.
Split into simpler sentences: Remoter land was granted to a magnate ("lord " or"earl") who was rewarded for the greater effort of subduing the natives with a greater autonomy. Such grants specified vague territorial limits within which they were permitted to administer as much land as they could conquer.