She had, indeed, given up her position as queen of the less to be vassal of the greater.
King Gunther receives the fair Recken into his service as a vassal.
The second is a king who was a vassal of Tiglath-Pilezer, king of Assyria.
The Duke looked sharply at him, then turned his gaze on his vassal.
Highness—tell me, your Highness, a vassal doesn't amount to much, does he?