Plutarch De Heroditi malignate 13

[13] The same Herodotus, that he may still be like himself, says that the Persians learned the defiling of the male sex from the Greeks. ¹ And yet how could the Greeks have taught this impurity to the Persians, amongst whom, as is confessed by almost all, boys had been castrated before ever they arrived in the Grecian seas? He writes also, that the Greeks were instructed by the Egyptians in their pomps, solemn festivals, and worship of the twelve Gods; that Melampus also learned of the Egyptians the name of Dionysus (or Bacchus) and taught it the other Greeks; that the mysteries likewise and rites of Ceres were brought out of Egypt by the daughters of Danaus; and that the Egyptians were wont to beat themselves and make great lamentation, but yet he himself would not tell the names of their Deities, but concealed them in silence. As to Hercules and Bacchus, whom the Egyptians named Gods, and the Greeks very aged men, he nowhere feels such scruples and hesitation; although he places also the Egyptian Hercules amongst the Gods of the second rank, and Bacchus amongst those of the third, as having had some beginning of their being and not being eternal, and yet he pronounces those to be Gods; but to the Greek Bacchus and Hercules, as having been mortal and being now demi gods, he thinks we ought to perform anniversary solemnities, but not to sacrifice to them as to Gods. The same also he said of Pan, overthrowing the most venerable and purest sacrifices of the Greeks by the proud vanities and mythologies of the Egyptians. ²