Ancient and medieval sources from Greece to Korea speak of the morally reprehensible habits of the Persians, who engage in close-kin marriage. Indian Buddhist texts also preserve similar ideas. One interesting passage in a narrative text makes use of this motif in a particularly interesting way, thereby indicating the character who appeals to the trope as ethically beyond the pale. The present paper explores the background of this common depiction of Persian marriage customs for its own intrinsic interest, and as a means to explicate the passage in question.