Kautilya's Arthashastra 7.18.5

7.18.5

madyamaś ced vijigīṣor mitraṃ mitrabhāvi lipseta, mitrasyātmanaś ca mitrāṇy utthāpya madhyamāc ca mitrāṇi bhedayitvā mitraṃ trāyeta //

If the madhyama king is desirous of securing the friendship of the conqueor's would-be friend, then having set his own and his friend's friends against the madhyama, and having separated the madhyama from the latter's friends, the conqueror should preserve his own friend; or the conqueror may incite the Circle of States against the madhyama by telling them; "this madhyama king has grown haughty, and is aiming at our destruction: let us therefore combine and interrupt his march."