 <unk> claimed that <unk> died from an <unk> seizure , but ancient historians all claim <unk> ' death came from <unk> 's poisoning him . <unk> , he enlisted the services of <unk> , a woman who specialized in the manufacture of poisons . She devised a mixture to kill <unk> , but after testing it unsuccessfully on a slave , <unk> angrily threatened to have her put to death if she did not come up with something usable . <unk> then devised a new <unk> that she promised would " kill <unk> than a viper . " 
