Heliodorus

Ethiopian Fantasy
 

8.17.2 When the Ethiopians were come to them, they knew Bagoas to be a eunuch by his face ...

8.17.4  For eunuchs are in the courts of Persia eyes and ears, who, because they have neither children nor relatives to whom their minds might be bent, depend only on him who has committed himself to them ...

9.25.5 "But what is he who stands by them, looking so like a eunuch?" One of the men who stood by answered that he was a eunuch indeed, whose name was Bagoas. "Let him go with you also, not as a sacrifice himself, but to see that this other maid ordained to be offered may be kept chaste until the time come that she will be offered." For eunuchs are very jealous, and therefore he appointed him take heed that the other do not that which they themselves are not able to do.