When a king thinks that, “Though successful, my ally may cause my army to move in an enemy's territory or in wild tracts, and during unfavourable seasons and thereby he may render it useless to me,” then under the excuse of having to employ his army otherwise, he may help his ally in any other way; but when he is obliged to lend his army, he may send that kind of his army, which is used to the weather of the time of operation, under the condition of employing it till the completion of the work, and of protecting it from dangers.
When the ally has finished his work, he should, under some excuse, try to get back his army or he may send to his ally that army which is composed of traitors, enemies, and wild tribes; or having made peace with the ally's assailable enemy, he may deceive the ally.
—Kautilya, in the Arthaśāstra, 7.8:28-33
