In a political relationship between two unequal nations, the more powerful and assertive nation is called the 'suzerain,' while the weaker, submitting nation the 'vassal.' Suzerainty and vassalship are the corresponding nouns.
Such relationships were, in the ancient Near East, defined by treaties or covenants which spelled out the conditions to which (mainly) the vassal must abide. Israel and Judah were made vassals during different times to Assyria and Babylon; it was their respective responses to these vassalship that shaped the most significant events and outcomes of their later history in the land. There was a time a few decades back when scholars were wont to think of the book of Deuteronomy as modeled on such treaties; it is now generally recognized that such theories can no longer be sustained.
©ALBERITH