Sentence:  When a large kingdom <WSD>abases</WSD> itself to a small principality, it acquires that principality, and when a small state <WSD>abases</WSD> itself to a large one, it obtains service (or protection) under the large one. It is for this purpose that the small state submits, and the large kingdom annexes the small states for the purpose of uniting and maintaining the people. 
Meaning of the word marked with <WSD> tags:  To lower, as in condition in life, office, rank, etc., so as to cause pain or hurt feelings; to degrade, to depress, to humble, to humiliate. (from c. 1350–1470)<ref name=SOED/>