Two of the king’s officials, Bigtan and Teresh, sought to assassinate Ahashverosh, but Mordekhai exposed their plot and saved him.

Rabbi Yohanan said: Bigtan and Teresh were two Tarsians, and they would converse in the Tarsian language. They said: From the day that Esther arrived we have not slept. Come, let us put poison into his goblet so that he will die. But they did not know that Mordekhai, as a member of the Sanhedrin, was one of those who sat in the Chamber of Hewn Stone, and that he knew seventy languages. (Megilla 13b)