'Vassal' in the Bible

He also took some of the seed of the land (Zedekiah, of the royal family) and planted it in fertile soil and a fruitful field; he placed it beside abundant waters and set it like a willow tree.

As I live,’ says the Lord God, ‘surely in the country of the king (Nebuchadnezzar) who made Zedekiah [the vassal] king, whose oath he despised and whose covenant he broke, in Babylon Zedekiah shall die.